Good Growing Practices - an Overview for Beginners
My hope is that this thread becomes a gathering place for beginners and the experienced alike, a place where reliable information that is rooted in sound science and horticulture can be found. We’ll see how that ‘gathering’ part goes, but I have enjoyed enthusiastic participation on many of my other threads, so I am optimistic.
As I consider what I am going to share with you and how to go about sharing it, I am compelled to offer some background that will hopefully allow you some degree of comfort in placing some measure of value on my commentary. I enjoy the growing experience tremendously. I have worked hard toward increasing my skill level for more than 20 years, and I look at sharing what I have learned about the growing sciences as a natural extension of the enjoyment I get from nurturing plants - sort of nurturing people who nurture plants. I am invited to lecture frequently in the mid-MI area, and occasionally beyond. I lecture, conduct workshops, and do demonstrations on a variety of subjects related to growing, but most frequently I talk about things related to container culture, with maintaining houseplants being one of the most requested topics. I also enjoy participating here on Dave’s and at another popular garden forum. Hopefully we will be using some links to some of my other offerings here that will help you share some of the confidence others have in the reliability of my offerings. Those that know me know I am not after recognition or glory, I simply feel I can help any beginner with a willingness to learn and apply the newfound information, as have so many others, and I get a large measure of personal satisfaction from the feeling I may have helped someone along the path to becoming a better grower.
The first challenge is to offer information that a beginner can digest, and in such a way that he or she feels it is important enough to act on. I am first going to flesh out the main issues that, if understood, will make anyone a better grower and hope I’ve created enough interest that there will be plenty of questions so I can go into greater detail in the answers. For what it is worth, I tend to look at growing anything in containers from the perspective of what is best for the plant, not what is best for the grower. Far more often than not, the two ideas are mutually exclusive, so if grower convenience is a large priority of anyone reading this, there is not much sense in reading on. Growing well does take a little thought and a little effort.
The houseplants we grow are perennials nearly all, capable of growing for many, many years and of being passed from generation to generation. With attention to the areas I’ll cover in this post, you will discover you can maintain your plants in good health for as long as you continue to commit to providing favorable cultural conditions. Your plants are all genetically programmed to grow well and look beautiful. It is only our lack of knowledge and skill in the area of providing the cultural conditions they prefer that prevents them from growing to their potential. That sounds harsh, but it’s the truth.
I have never seen anyone other than me discuss growing plants in containers from this perspective, that is (and it bears repeating) your plants are already genetically programmed to grow well and look beautiful, but it’s up to you as a grower to eliminate the limitations so often associated with growing in containers. This post is about isolating some of the factors that are commonly the most limiting and helping you to reduce the limiting effects. For more information on the concept of limiting effects, do a search using the words “Liebig’s Law of the Minimum“
Soil choice - Growers should realize that the most important choice they will make when establishing a new planting or when repotting is their choice of soil. A poor soil is probably behind more than 90% of the issues that growers come to the forums seeking remedial help for. Collapsed or dead plants, spoiled foliage, insect infestations, disease issues are all symptoms usually traceable directly or indirectly to a poor soil. This is so important to understand, that I will devote the bulk of my effort toward making it clear why I offer this contention.
Light is extremely important to plants. Plants make their own food, using water, CO2, and energy from the sun. Inadequate light means the plant cannot make enough food to grow to the potential it was genetically programmed for. I will not go into great detail about light because when it comes to houseplants, you either have good light or are forced to deal with the limiting effects of inadequate light. If the thread takes off, we can discuss supplementing light and how to prune to help compensate for the leggy appearance caused by insufficient light, or other topics of interest relating to light.
Nutrition supplementation is a requirement for normal growth and good health when growing plants in containers. In the earth, many of the nutrients are supplied by minerals in the soil. Container soils usually have no mineral component (and it is best that they don’t in most cases - more later), and the sol components break down so slowly and are washed from the soil so quickly that deficiencies are virtually assured if you do not fertilize.
Repotting vs. potting up - that there is a difference is a concept foreign to most hobby growers. One practice ensures your plants will at least have the opportunity to grow to their genetic potential within the limits of other cultural conditions; that would be repotting, with it’s accompanying root maintenance, complete or partial bare-rooting, and a change of soil. Potting up, on the other hand, only temporarily allows the plant to grow a little closer to its genetic potential before root congestion and a lack of fine roots quickly returns the plant to the state of limited growth and vitality it was experiencing before potting up.
Watering habits - extremely important and inextricably linked to soil choice, which is why I saved it until the end - so it would lead me back to the most important consideration - the one most apt to determine the difference between frustration and a rewarding growing experience.
Air is as important as water in soils. Plants absolutely love plenty of air, and rebel very quickly at too much water in the soil. I’m going to describe what happens when you water plants growing in a soil that retains too much water. There are actually two possibilities. The first is, you water, and a part of the soil near the bottom of the container does not drain. This water has a name, it is called ‘perched water‘, so named because it ’perches’ (like a bird) in the soil above the pot bottom. This excess water is critically important because it very quickly begins to kill roots growing near the bottom of the pot, within hours. The first roots to die are the roots that do the lion’s share of the work - the very fine roots often referred to as ’hair roots’. The longer the soil remains saturated, the larger the diameter of the roots killed. When air finally returns to this once saturated soil, roots then begin to regenerate. This takes energy and is extremely expensive to the plant in terms of that energy outlay. The plant is actually forced by chemical messengers that tell it to ’grow roots’, to direct energy that would have gone into growing more leaves, branches, blooms, fruit, or just increasing the overall mass of the plant, to replacing the lost roots.
The second thing that might happen when you water if you are using a water retentive soil is, you water in small sips to prevent root rot. It makes sense to only give the plant a little water at a time - right? That might be a workable option if you have the luxury of using water that has been processed through a reverse osmosis water filter, or if you are watering with distilled water, but regular tap water has things dissolved in it, like magnesium, calcium, iron, sulfur, and others. If you water in ’sips’, these dissolved solids remain in the soil and build up over time. This has an impact on the plant’s ability to absorb water and the nutrients dissolved in water. To illustrate the potential impact these dissolved solids have on a plant, picture in your mind what curing salt does to ham or bacon. It literally pulls water from the cells & dries out the meat. Any solute in the solution surrounding plant roots can have the same potential effect on plant cells. It can make it difficult for plants to absorb water and nutrients, it can make it impossible, and in some cases can actually reverse the flow of water so it moves OUT of cells, effectively collapsing and killing them. We commonly call this ‘fertilizer burn’, but it doesn’t necessarily have to result from an over-application of fertilizer. When people come here wanting a remedy for foliage that is dying, with dried edges & tips, it’s almost always from over-watering and the accompanying limitation that has on root function and metabolism, or a high level of dissolved solids from fertilizers and tap water having accumulated in the soil making it difficult for the plant to take up water. Misting cannot correct a problem related to over-watering or a high level of solutes in your plant’s soil. Low humidity can be a contributing factor to the common symptoms of necrotic (dead) leaf tips and margins (edges), but for the actual cause, look to impaired root function from over-watering or a high level of dissolved solids in the soil. BOTH of these conditions are nearly always linked to a poor soil.
When using water-retentive soils, it seems almost as though we are on the horns of a dilemma. If we water generously, we risk the soil remaining saturated so long it causes root rot, or at a minimum - impaired root function. If we water sparingly, in small sips, we risk an accumulation of dissolved solids from tap water and fertilizer solutions in the soil …… so what to do? Well - I think we should look at an option that solves both issues and makes things much easier for the grower, while also providing the grower with considerably more latitude when it comes to watering and fertilizing.
The factor that determines how water retentive and difficult to grow in a soil is, is the size of the particles it is made from. The smaller the particles - the greater the water retention and the greater the degree of difficulty for growers. Soils made of any combination of peat, coir, compost, sand, topsoil, and other fine particulates are going to be very water retentive, which we know is undesirable from the perspective of the plant, and they cannot be suitably amended to correct drainage or the height of the perched water by adding perlite or other drainage material. If anyone disagrees with that statement, please ask for an explanation before mounting an argument or offering individual observations. Adding perlite to soils reduces the overall water retention of the soil, but it does nothing measurable for drainage (flow-through rates) or the height of the perched water table, the later being the critical consideration when it comes to a healthy root zone.
Soils made of a high % of pine bark or other inorganic particles will have lots of large air spaces called macropores. These are pores that will not hold water, only air, even when the soil is as saturated is it can be. They are critical to a healthy root zone. If you build a soil with plenty of air space, it hardly matters what the soil is made from. What is important is how the soil is structured. I will grow a perfectly healthy plant in a bucket of broken glass on a dare and a wager if anyone is interested in taking me up on it. If you have a soil with a healthy structure, a good nutritional supplementation program, and have good available light, the rest is so easy anyone can do it - honest. I’ve seen it happen over & over and over again. You will not go wrong if your primary focus is providing a healthy - a truly healthy environment for roots. Roots are the heart of the plant. Roots come first. If you cannot keep the roots happy, there is no chance you can keep the rest of the plant happy. That was a paraphrased quote from Dr. Carl Whitcomb, PhD, who wrote the bible on “Plant Production in Containers”.
This ends the beginning discussion about soils. Until you are able to grow plants, the growth rate and appearance of which you are happy with, focusing on removing the limitations placed on your plants by soil choice will almost always constitute the best use of your energies. After reading this far, if nothing else, I hope you take that from this offering. It is the most important point and the best piece of advice I can give you. If you are interested in knowing HOW to make soils that will help you remove the limitations, now is the time to ask.
Nutrition is an area that is very misunderstood when it comes to container culture, but it is actually very easy. It’s also very easy to become confused because there are so many numbers that represent different fertilizer NPK percentages and so many different kinds of fertilizers. I will need to use some numbers, but I think an understanding of NPK percentages as opposed to fertilizer RATIOS is important. NPK %s tell us how much (N)itrogen, (P)hosphorous pentoxide, and (K) potassium oxide (the symbol for potassium is ’K’) are in a fertilizer by weight. So a fertilizer that is labeled “All Purpose 24-8-16” is 24% nitrogen, 8% phosphorous, and 16% potassium. 12-4-8 is also a common “all-purpose” fertilizer. It has exactly half the nutrients of 24-8-16, but both are 3:1:2 RATIO fertilizers. Ratios are a way of describing the amount of nutrients in a fertilizer as they relate to each other. Why is this important? It is important because we know that on average, plants use about 6 times as much N as P, and they use about 3/5 as much K as N, and now I will tell you how we can use this information to our plant’s advantage.
The ideal way to fertilize is to supply fertilizer at the same ratio in which plants use the nutrients. The reason is because optimal growth and vitality can be had only when nutrients are in the soil at overall levels low enough that it doesn’t become difficult for plants to take up water and nutrients dissolved in that water. Remember what we said above about a high level of soluble in the soil making it difficult for roots to absorb water and nutrients? Nutrients also need to be present at levels high enough to prevent deficiencies. If we think about it for a second, we can see that the best way to achieve this end is to supply nutrients at the same ratio in which they are used.
I noted that the NPK percentages actually tell us how much phosphorous pentoxide and potassium oxide are in a fertilizer so I can show you how fertilizer manufacturers arrived at a 3:1:2 ratio as their “all-purpose” blend. Only 43% of the P reported on a fertilizer label is actually P, and only 83% of the K reported is actually K. Once you apply these factors to any of the 3:1:2 ratio fertilizers (24-8-16, 12-4-8, and 9-3-6 are all popular 3:1:2 ratios, you’ll see they supply nutrients in almost exactly the same ratios as the average that plants actually use, and these fertilizers are excellent at keeping overall levels of soluble as low as they can be without nutritional deficiencies.
There is no need to use specialty fertilizers; and many specialty fertilizers, like the advertised “bloom boosters” with up to 30 times more phosphorous than a plant could ever use (in relation to the amount of N used) can be moderately to severely limiting because the excess nutrients are a limiting factor.
The question often arises, “Should I use a synthetic or an organic fertilizer”? The answer is: Use whichever you wish; but the qualifiers are: Organic fertilizers are actually more accurately called soil amendments. They are mixed into the soil in the hope that at some point soil organisms will digest them and make them available in elemental form so plants can absorb them. The problem with that approach is that the populations and activity of soil life populations in containers are erratic and unreliable, making the delivery of nutrients from organic sources just as erratic and unreliable. What you apply today, may not be available until next month, and there is no way to determine what residual amounts of which elements remain in the soil. Soluble fertilizers like Miracle-Gro and others are completely available as soon as applied, and we know exactly what our plants are getting. They are simply much easier to use and deliver nutrients much more reliable than other fertilizer types. You can lump controlled release fertilizers like Osmocote and others in with the soluble synthetic fertilizers. With them, you get an extra measure of convenience but sacrifice a measure of control. As with all fertilizers, it is important to note the NPK percentages to be sure you are supplying the fertilizer in a favorable ratio if you want your plants to be all they can be.
It isn’t going to kill your plants if you use a fertilizer with a less favorable ratio because plants tend to take the nutrients they need from the soil (solution) and leave the rest, but it is important to understand that it is ’the rest’ that constitutes a limiting factor, so avoiding excessively high levels of any one nutrient whenever possible is to your (plant’s) benefit.
As noted above, most growers draw no distinction between ‘repotting’ and ‘potting up’. I have spent literally thousands of hours digging around in the root-balls of containerized plants. Old plants from nurseries of greenhouses are probably the closest examples to what most houseplants are like below the soil line, so I'll offer my thoughts for you to consider or discard as you find fitting.
I have helped salvage many plants that had been containerized for long periods and were ‘circling the drain’. Not long ago, our bonsai club invited a visiting artist to conduct a workshop on mugo pines. The nursery (a huge operation) where we have our meetings happened to have purchased several thousand of the mugos somewhere around 10 - 12 years ago and they had been potted up into continually larger containers ever since. Why relate these uninteresting snippets? In the cases of material that has been progressively potted-up only, large perennial roots occupied nearly the entire volume of the container, plant vitality was in severe decline, and soil in the original root-ball had become so hard that in some cases a chisel was required to remove it.
In plants that are potted up, rootage becomes entangled. As root diameters increase, portions of the roots constrict other roots and impair the flow of water and nutrients through them, much the same as in the case of girdling or encircling roots on perennials grown in-ground. The ratio of fine, feeder roots to more lignified (woody) and perennial roots becomes skewed to favor the larger, and practically speaking, useless roots.
The initial symptoms of poor root conditions are progressive diminishing of branch extension on plants that branch, loss/shedding of foliage on the parts of branches nearest to the ‘trunk’, often giving the plant a ‘poodle look’, and reduced vitality. As rootage becomes continually compressed and restricted, branch extension stops and individual branches might die as water/nutrient movement is further compromised. Foliage quality may not (important to understand) indicate the tree is struggling until the condition is severe, but if you observe your plants carefully, you will find them increasingly unable to cope with stressful conditions - too much/little water, heat, sun, etc. Trees that are operating under conditions of stress that has progressed to strain, will usually be diagnosed in the end as suffering from attack by insects or other bio-agents/disease while the underlying cause goes unnoticed.
I will mention again that I draw distinct delineation between simply potting up and repotting. Potting up temporarily offers room for fine rootage to grow and do the necessary work of water/nutrient uptake, but these new roots soon lignify, while rootage in the old root mass continues to grow and become increasingly restrictive. The larger and larger containers required for potting up & the difficulty in handling them also makes us increasingly reluctant to undertake even potting up, let alone undertake the task of repotting/root-pruning, which grows increasingly difficult with each up-potting.
So we are clear on terminology, potting up simply involves moving the plant with its root mass and soil intact, or nearly so, to a larger container and filling in around the root/soil mass with additional soil. Repotting, on the other hand, includes the removal of all or part of the soil and the pruning of roots, with an eye to removing the largest roots, as well as those that would be considered defective. Examples are roots that are dead, those growing back toward the center of the root mass, encircling, girdling or j-hooked roots, and otherwise damaged roots.
I often explain the effects of repotting vs potting up like this:
I will rate growth/vitality potential on a scale of 1-10, with 10 being the best. We're going to say that plants in containers can only achieve a growth/vitality rating of 9, due to the somewhat limiting effects of container culture. Lets also imagine that for every year a plant goes w/o repotting or potting up, its measure of growth/vitality slips by 1 number, That is to say you pot a plant and the first year it grows at a level of 9, the next year, an 8, the next year a 7. Also imagine please, we're going to go 3 years between repotting or potting up.
Here's what happens to the plant you repot/root prune:
year 1: 9
year 2: 8
year 3: 7
year 1: 9
year 2: 8
year 3: 7
year 1: 9
year 2: 8
year 3: 7
You can see that a full repotting and root pruning returns the plant to its full potential within the limits of other cultural influences for as long as you care to repot/root prune.
Looking now at how woody plants respond to only potting up:
year 1: 9
year 2: 8
year 3: 7
year 1: 8
year 2: 7
year 3: 6
year 1: 7
year 2: 6
year 3: 5
year 1: 6
year 2: 5
year 3: 4
year 1: 5
year 2: 4
year 3: 3
year 1: 4
year 2: 3
year 3: 2
year 1: 3
year 2: 2
year 3: 1
This is a fairly accurate illustration of the influence tight roots have on a plant's growth/vitality. You might think of it for a moment in the context of the longevity of bonsai trees vs the life expectancy of most trees grown as houseplants, or the difference between less than 4 years versus more than 400 years, lying primarily in how the roots are treated.
I have not yet mentioned that the dissimilar characteristics of the old soil as compared to the new soil when potting-up also carries the potential for trouble. With a compacted soil in the old roots and a fresh batch of soil surrounding the roots of a freshly potted up plant, it is nearly impossible to establish a watering regimen that doesn't keep the differing soils either too wet or too dry, both conditions occurring concurrently being a limiting factor and the rule rather than the exception.
Most who read this would have great difficulty showing me a containerized plant that is more than 10 years old and as vigorous as it could be, unless it has been root-pruned at repotting time; yet I can show you hundreds of trees 20 years to 200 years old and older that are in perfect health. All have been root-pruned and given a fresh footing in in new soil at regular and frequent intervals, the same treatment all my houseplants get.
Thanks to any/all who made it this far. This is only an overview, but with even a rudimentary understanding of how to go about reducing the effects of the limiting factors that restrict growth and vitality, I know you can improve on how well your plants can grow, as well as on the degree of satisfaction you get from your growing experience - my only reasons for writing this. Hopefully the offering leaves you with many questions.
I am new to gardening of all kinds. I am using your 'gritty mix' for all of my indoor plants as well as Dyna-Gro Foliage Pro and they are all thriving. I plan to start some perrenials and annuals from seed this coming winter/early spring for next years outside container and landscape plants. Can I use the 'gritty mix' as a seed starting medium or is there an alternative that you could recommend. I want to use a mix that provides high germination rates as well as minimizes, or preferably, prevents damping off. This is my first time starting seeds. Please help!!!
Hi, Linda. Thanks for helping to get the thread of the ground. I was beginning to wonder ... ;-)
The two primary considerations when starting most seeds are a steady supply of moisture and a medium that doesn't support the fungaluglies that cause damping off diseases (phytophthora, pythium, Rhizoctonia solani ...). A 'steady supply of moisture' would be enough moisture to keep the medium 'damp but not wet' - about as damp as a wrung-out sponge is great. Soggy soils that don't hold enough air become the breeding ground for the listed fungi + others that cause the damping off diseases. Seedlings LOVE air in the root zone - LOTS of it. Ideal, would be a coarse medium like the gritty mix or a bark-based mix that would ensure good aeration - because it is literally built into the soil. I often use either the gritty mix or the 5:1:1 (pine bark:peat:perlite) mix to start seeds. What I usually do is start with at least 3" of medium. Spread seeds on top of the medium, then cover the seeds with a thin layer of peat (5:1:1) or Turface fines (gritty mix). I then mist the surface regularly to keep the moisture supply even and to guard against soggy soil which is the real killer.
Commercial seed starting mixes rely on the fact that the mix is made from peat, which has such a low pH that it is almost sterile, and vermiculite, which would be considered sterile because it is fired at such high temps. The problem with these mixes is the fact that they are VERY water retentive, compact easily, and rely on the good watering sense of the grower to keep the medium properly moistened, which as we know doesn't always work out according to intent.
Most seeds germinate fastest at temps from 65-70*. Air temperatures somewhat cooler (about 10*) than root temperatures seems to promote best seedling growth, so a propagation mat (sort of a waterproof heating pad for hort applications) used up to the onset of seedling emergence (then discontinue bottom heat) is helpful as long as soil temps don't get too high above 70*. Begin fertilizing when the first set of true leaves appears; until then, the seedling gets its nutrition from the seed's endosperm.
Good Morning Al,
Thanks again for all the expert help. You've made seed starting so clear and simple. I was so confused by all of the different methods discussed on the seed germination forum. I now look forward to propagation...which says alot coming from a former "double-dipped brown thumb".
You're welcome - my pleasure. Don't forget asexual propagation from cuttings, air or ground layering or even stooling, and divisions, as a way to make more plants. I often pinch many of the plants I buy as soon as I get them & use the cuttings to start more plants for myself or to share.
I too enjoyed your messages on beginning houseplants. This fall I am planting more seeds than in the past simply due to over half of my seeds did not develop.
I did plant ornamental kale in the beginning of Sept. with not much success. I am planning on trying again this weekend. I am using seed starter soil and viable seeds from Twillyseeds.com. It is a challenge to keep the right moisture at all times. I do have a greenhouse to use if the weather gets a little too nippy.
I do appreciate the kind words, Peg. I try hard to make sure you guys get information you can rely on as scientifically and horticulturally sound - so you at least can make informed decisions when they're necessary. I realize that not everyone wants to put the same amount of effort into growing and learning, but a little effort and a little knowledge can go a long way toward making us better growers. Hopefully this thread ends up being a place folks feel they can come to for help departing from limiting habits, instead of encouragement to change something minor and go on with business as usual.
Thanks for your comments and good luck with the kale. What are you planning on using for fertilizer?
Hm, I've always been told NOT to mess with the roots... I'm about to repot some of my plants... How do you cut roots back? How do you know which ones, and how do you get to the ones in the center of the root ball? Or am I reading this wrong? I have a healthy Ficus Benjamina, and I can just see it dropping every last leaf if I cut the roots back so much...
There is a LOT of misinformation that is perpetuated by people who don't really understand why they parrot what they heard or read somewhere. That you should never 'mess with roots' is one of those horticultural myths that when looked at from a more scientific perspective, won't hold up to even casual examination.
Cases in point from the practical perspective: I have some 300 plants growing on as potential bonsai. They ALL regularly (every year or every other year is the norm) have anywhere from 1/3 - 3/4 of their roots removed for the express purpose of eliminating the limiting effect of tight roots and to rejuvenate the plant. Large roots in the root mass of containerized plants serve no purpose other than as conductive plumbing. It's the fine roots that do all the heavy lifting, so anything you do that increases the number of fine roots increases growth and vitality. How do you increase the number of fine roots? The same way you increase the number of fine branches in the canopy - by pruning and pinching.
Also - in spring, when I'm building the 30-40 mixed display containers I have scattered through the decks & gardens, I'll use a lot of bedding plants & plants in 3-4" containers. Often, these plants are VERY root bound. Recognizing the permanent negative effect that condition has on plants, I immediately correct it as a matter of course by ripping the bottom 1/2 - 2/3 of the roots off the plant and running my fingers up into the root mass to separate and spread roots before the plants are potted in the mixed (or specimen/singular) plantings. I also treat all plants I buy in similar fashion. I've posted thousands of pictures here & at Garden Web that show a very wide variety of plants that are obviously robust and exhibiting unblemished foliage & prolific blooms - so it works. 'Root work' is the reason bonsai trees can be passed from generation to generation in perfect good health, while most houseplant growers have great difficulty pointing to a plant more than a few years old that could be considered in excellent or even good health.
The rest of the reason 'why': We already saw that pruning roots increases the number of fine roots that do all the heavy lifting, But there is another factor involved. We tend to think of the age of plants in the same manner we think of age in humans or animals - chronologically. We, like plants, go through several life stages - embryonic, juvenile, adolescent (intermediate in plants), and mature, are stages roughly mirrored in plants. Where we vary greatly is in the way our cells age. In animals, body cells all mature at approximately the same speed. Plants grow by consecutive divisions of cells at the growing points (meristems), so their various parts are different ages (the top of the plant is younger than the basal portion, chronologically, but older ontogenetically because it took more cell divisions for the part of the plant to be at the top or the end of a branch.
Why is that important? Because tissues tend to RETAIN their genetic vigor. That is to say tissues growing nearest to the point where the top of the plant transitions to roots are the most vigorous tissues and they retain that vigor. So, when you cut a plant back hard, you cut it back to more vigorous tissues. Often, growth will 'explode', with the plant back-budding profusely when you cut it back hard. This holds true as much below the soil line as above.
You may be familiar with the practice of 'rejuvenation pruning that is undertaken to restore the vigor of plants in the landscape. The term comes from the fact that this type of pruning restores the plant to a point where it is growing from more juvenile tissues. It shouldn't be much of a surprise to learn that roots as well as shoots can be rejuvenated by way of the same mechanism.
We KNOW that once roots become congested to the point the root/soil mass can be lifted intact, that growth and vitality are impacted negatively, which is why potting up (as seen in the OP) is a limiting practice and repotting with its accompanying root work rejuvenates.
If you have any other questions, or there is anything you're not clear on, please don't hesitate to ask. I admire anyone who wants to learn & isn't afraid to ask questions.
Hm... OK, I get it... But, do you still pot in a bigger pot that the plant was in after you cut the roots back? When you cut the roots back, do you only do it when you are putting the plant in a bigger pot, or just when that 1-2 year mark hits? Again, sorry if you already answered this..
Peg - you probably won't get any benefit from the root stimulant, but ... What are the NPK% of your fertilizer?
TR - I'll end with some thoughts on what REALLY determines what size pot is appropriate for what size plant. You'll be surprised to learn it's the soil - not how big the plant is or the size of the pot it was last in.
2 things determine whether or not a repot with root pruning is in order is 1) is it an appropriate time to do a full repot. Almost all houseplants, unless winter growers, are best repotted in the summer, in the month prior to their most robust growth. 2) how congested the roots are, and how congested they are GOING to be when the next appropriate time to repot rolls around. Growth becomes affected at about the state of root congestion where the root/soil mass can be lifted from the container intact. A reasonable guideline would probably be found in asking yourself this question at the appropriate time for repotting, "Will the plant reach that point of root congestion before it's less than half way through its most vigorous growth period?" If the answer is yes, it should probably be repotted. If the answer is no, it can probably wait another year.
In many cases, repotting (as opposed to potting up) allows you to use the same pot for a number of years before the plant outgrows it. You remove the old soil, reduce the roots by 1/3-2/3, and put the plant back in the same pot in fresh soil. After only a few repots, you'll know intuitively when the plant needs a larger pot. Which is the perfect lead-in to what determines appropriate pot size.
Here's a copy/paste job of something I wrote a while back:
How large a container ‘can’ or ‘should’ be, depends on the relationship between the mass of the plant material you are working with and your choice of soil. We often concern ourselves with "over-potting" (using a container that is too large), but "over-potting" is a term that arises from a lack of a basic understanding about the relationship we will look at, which logically determines appropriate container size.
It's often parroted that you should only move up one container size when "potting-up". The reasoning is, that when potting up to a container more than one size larger, the soil will remain wet too long and cause root rot issues, but it is the size/mass of the plant material you are working with, and the physical properties of the soil you choose that determines both the upper & lower limits of appropriate container size - not a formulaic and zombie-like upward progression of container sizes. In many cases, after root pruning a plant, it may even be appropriate to step down a container size or two, but as you will see, that also depends on the physical properties of the soil you choose.
Plants grown in ‘slow’ (slow-draining/water-retentive) soils need to be grown in containers with smaller soil volumes so that the plant can use water quickly, allowing air to return to the soil before root issues beyond just impaired root function/metabolism become a limiting factor. We know that the anaerobic (airless) conditions that accompany soggy soils quickly kill fine roots and impair root function/metabolism. We also know smaller soil volumes and the root constriction that accompany them cause plants to both extend branches and gain o/a mass much more slowly - a bane if rapid growth is the goal - a boon if growth restriction and a compact plant are what you have your sights set on.
Conversely, rampant growth can be had by growing in very large containers and in very fast soils where frequent watering and fertilizing is required - so it's not that plants rebel at being potted into very large containers per se, but rather, they rebel at being potted into very large containers with a soil that is too slow and water-retentive. This is a key point.
We know that there is an inverse relationship between soil particle size and the height of the perched water table (PWT) in containers. As particle size increases, the height of the PWT decreases, until at about a particle size of just under 1/8 inch, soils will no longer hold perched water. If there is no perched water, the soil is ALWAYS well aerated, even when the soil is at container capacity (fully saturated).
So, if you aim for a soil (like the gritty mix) composed primarily of particles larger than 1/16", there is no upper limit to container size, other than what you can practically manage. The lower size limit will be determined by the soil volume's ability to allow room for roots to ’run’ and to furnish water enough to sustain the plant between irrigations. Bearing heavily on this ability is the ratio of fine roots to coarse roots. It takes a minimum amount of fine rootage to support the canopy under high water demand. If the container is full of large roots, there may not be room for a sufficient volume of the fine roots that do all the water/nutrient delivery work and the coarse roots, too. You can grow a very large plant in a very small container if the roots have been well managed and the lion's share of the rootage is fine. You can also grow very small plants, even seedlings, in very large containers if the soil is fast (free-draining and well-aerated) enough that the soil holds no, or very little perched water.
I have just offered clear illustration that the oft repeated advice to ‘only pot up one size at a time’, only applies when using heavy, water-retentive soils. Those using well-aerated soils are not bound by the same restrictions.
Thank You for this thread Al. I printed it and took my time reading it and have enjoyed the learning. I now need to find your other threads on soil and copy them. I did have a question on pruning to compensate for the artificial light I have to provide for some of my plants in the winter. I'm always afraid to prune for fear I will kill them. Needless to say come spring when they go outside I deal with long leggy plants that I know need pruned.
Actually, I was just asked (a couple of days ago, over at Garden Web) to start a thread about the very basic concepts of pinching & pruning - about what happens when you DO pinch or prune and how to use it to your advantage, and how to use it to keep YOU in control instead of the plant. There really is no reason to have an unruly plant sprawling hither and yon, when all it takes is a rudimentary understanding of how 2 growth hormones work against one another (antagonistically) in a fight for control of how the plant will grow, and a little intervention on our part to tip the scales gently in favor of one or the other. ;-)
For now though, it's probably better to think 'pinching' from Aug-Jun, and any hard cutting back or heavy pruning from Jun-Aug. It's important to take into account the plant's energy levels and energy flow when you start do do anything drastic. Plants are VERY forgiving if you give them a chance to gather their reserves before you heap indignities on them - not so forgiving if you don't consider how strong they are (or aren't) and just go about things willy nilly.
It doesn't take much effort to gain a little understanding about how plants work; and the knowledge you claim will serve you for as long as you tend plants. I guess you could say that knowledge is a gift that keeps on giving - especially when you 'pay it forward'.
It was quiet for so long, I was afraid it wasn't going to take off.
You had mentioned the other threads about soils & I forgot to post a link. You'll find 2 older threads as stickies at the top of the container gardening forum, but this is an extension of those threads. I guess they were getting so long they were slow to load for some, so they asked for a continuation. Here's the thread that's most recent, even though no one's requested it be made a sticky yet: http://davesgarden.com/community/forums/t/1073399/
MYTH - with a small qualifier. Here is something I wrote a while back that hopefully dispells the myth and explains why it's parrotted and perpetuated so widely:
I would like to talk a little about, and hopefully dispel the myth that certain plants 'like' or 'prefer' to be grown tight (under root-bound conditions). Maybe we can also understand that no plant will 'do well' when it's pot-bound if you are using a plant with plenty of room for its roots to run as your standard of judgment. If plants did better growing under root-bound conditions, Mother Nature would have arranged for in situ (where they naturally occur) plants to grow with their roots in tight little cones or cubes, yet we never see that occur. While it's true that we may be sometimes be able to use the STRESS of our plants being root-bound to bend plants to our will and achieve OUR goals, the fact is that this serves US well, and not the plant.
Let's examine what 'growth' is. Growth is simply a measure of the increase in a plant's biomass, how much bigger it has become (the weight of the sum of its parts), and is the actual measure of how 'well' a plant is doing. We know that tight roots restrict growth, reduce the amount of branch/stem extension, and reduce the potential for an increase in mass, so even if we THINK plants are doing well because we use the stress of tight roots to get them to bloom or grow in a particular habit that we like, the truth is tight roots are stressful, and plants would rather have plenty of room for their roots so they could grow as mother nature intended. No one is more aware of the negative influence tight roots has on growth than the bonsai practitioner who uses that tool extensively to bind down the plant's growth habits so the will of the grower, not the plant, prevails. Using tight roots as a tool to achieve an end is all about the grower's wants, and not the plant's.
Interestingly, many mistake the fact that a plant seems to be extending and growing leaves for actual growth, but if the plant is robbing nutrients from other parts and then shedding them in order to support new leaves or branch extension, it may not be increasing in mass, and therefore not growing ... only robbing Peter to pay Paul.
If we chase the 'root-bound issue' a little further, we can see the reasons that it is suggested that particular plants might like root-bound conditions. Tight roots alters the plant's growth habits, and the stress of tight roots can cause other physiological responses, like bloom induction. Again, this is happening because of stress, and is the plant's unhappy response. Bright flowers make the grower happy, but the plant's perspective may be entirely different.
Where I was really heading when I started to write this is: There is a relationship between plant mass (size), the physical characteristics of the soil, and the size of the container. In many cases, when we are advised that plant X prefers to be grown tight, we are being told that this plant won't tolerate wet feet for extended periods. Someone somewhere assumed that we would be growing this plant in an out-of-the-bag, water retentive soil, and "a big pot of that soil stays wet for a long time, so we better tell these people to grow this plant in a tiny pot so the plant can use the water in the soil quicker; then, air will return to the soil faster and roots won't rot."
If you place a plant in a gallon size pot of water-retentive soil, it might use the water fairly quickly, at least quickly enough to prevent root rot; but if you put the same plant in 5 gallons of water-retentive soil, the plant will take 5 times as long to use the water and for air to return to the soil, making it much more probable that root rot issues will arise. So lets tell 'em to grow these plants tight to save them (the growers) from themselves ... because we KNOW they're all going to be using a soggy soil.
The key here, is the soil. If you choose a very porous soil that drains well and supports no (or very little) perched water (perched water is that water in the saturated layer of soil at the bottom of the pot), you can grow a very small plant in a very large pot and make the plant MUCH happier than if you were growing it tight. You still have the option of choosing those plants you prefer to stress intentionally (with tight roots) to get them to grow as YOU please; but for the others, which comprise the highest %, it makes much better sense to change to a soil that allows you to give the plant what it wants (room for roots to run) than to stress the plant (with tight roots) so it won't die (from root rot due to an excessively soggy soil). That's a little like keeping your dog in a sleeping bag 24-7 to ensure he doesn't get cold.
Hi Al, Where do you prchase or find the growing mediums you use. Do I find the fir bark at a place that makes mulch ? Can I get the chicken grit at a farm store and we have a stone and rock quarry close. Can I find the Turface there. I'm really interested in this, you have posted some amazing pictures.
I make all my own mediums, but I basically use 2. The reason I use them is they are much easier and much more productive. I don't need to worry about over-watering, root rot, or a build-up of salts in the soil from tap water & fertilizers.
Easiest to make is the mix based on pine bark fines. It consists of:
5 parts pine bark fines
1 part perlite
1 part sphagnum peat (or compost)
dolomitic (garden) lime @ 2-3 tsp per gallon or 1/3-1/2 cup/cu ft
When you're done, it will look like the mix in the middle (when dry). It's coarseness lends plenty of aeration to the soil and reduces or practically eliminates perched water, which is the real culprit, and normally the most limiting factor for growers using commercially prepared soils based on peat. Perched water in soils simply makes your job soo much more difficult ... you end up fighting against the effects of the soil instead of letting the soil work FOR you.
The bark you see in the picture above is what you need to look for. Unfortunately, the size of the bark is important, and it often takes some scouting to find something suitable. When it comes to deciding what soils are top notch and what soils are inappropriate to best vitality, size (of the particles) matters. I'll wait for questions before I go deeper, but I hope any others that are curious will consider joining in the conversation. I really think that beginners can take a giant step forward if they learn to get the soil right.
The gritty mix is what I use for all my houseplants and material growing on as bonsai, as well as my bonsai. It's a very coarse mix that looks more like gravel with a little bark in it, but it has terrific structure, it's really durable (lasts a LONG time) and super easy to grow in. I think it's important to understand that 'rich and black' soils are wonderful in the garden, but are often too water retentive to be well-suited to container culture. Container soils are all about structure. If you keep in the back of your mind that ensuring there is plenty of air in the soil for as long as the planned interval between repots is your #1 priority, you have it ... as long as you learn how to do it and follow through.
The gritty mix (These soils were named by others after they started using them. Both have a very large following, more so at Garden Web than here, but you can see how popular the information is by noting the degree of participation on the threads devoted to a discussion about soils on the Container Gardening forum.) is also comprised of 3 ingredients:
1 part of screened pine or fir bark
1 part screened Turface
1 part crushed granite or cherrystone (chicken grit in grower size or #2 cherrystone)
You should be able to get the Turface at John Deere Landscapes, 2020 Kelsey Ct in Fort Wayne, (260) 490-0041
The grit can be found at feed stores & grain elevators with stores that sell farm feeds. Skip the big box stores for Turface or grit. They might have suitable bark, but that's a deal where you find it when you find it. I have several places within a few miles where I can get it whenever I need it. For the gritty mix, I buy prescreened fir (orchid) bark in 1/8-1/4" size, but screened pine bark works just as well.
I think it's important to realize that it's not the 'recipes' that are of value, it's the concept found in the information I linked you to. The recipes are just good ways to implement the concept.
Thanks so much, I think what I'll do is start collecting all the mediums this winter and I'll be ready in the spring to do my repotting. I was buying cactus mix and that seemed to work pretty good. I did notice after reading about the PWT that I had a few plants this year that were rotting because of it...Wonderful Information! :) :)
This is so much good information, thank you for posting, Al. I have a lot of houseplants, the hubby takes care of them. I can see that while they are doing ok, they are not thriving.
He was always the 'inside guy', I took care of the outside stuff. The more I looked at the inside plants, the more I realized they weren't doing as well as they could. And then you started this thread.
I look forward to spring, and in the meantime will read all this good information you have been posting, and that I have printed out.
Thank you, Julie & Acts (did you ck 1631?). I think there are a lot of growing practices that could nearly be labeled 'traditional' that have built in limitations. The primary one is the tendency of beginners and experienced alike to grow in soils they can readily buy off the shelf. I'm not saying that you absolutely can't grow well in soils based on peat, compost, or other small particulates; it can be done, but it is much more difficult and takes a degree of understanding of soil science and plant physiology that isn't in the grasp of most hobby growers.
I think I mentioned that the soil is the foundation of every planting. Build a strong foundation, and you won't have to fight against the ill effects of a weak one down the road. I remember a commercial for an auto parts manufacturer from years ago. I think it was Framm. They were trying to get you to purchase their air and oil filters by using the motto, "You can pay me now [the screen changes to a greasy-looking mechanic] or you can pay me later." Growing houseplants is much like that. If you start with a poor soil, you'll be scratching your head and wondering how to fix the issues that arise from that choice, most of the time not even realizing the true source of those issues. If you start with a good soil, in most cases those same issues never surface. It is an extra effort to locate the ingredients & mix your own soil, though it is very easy and about half the cost of bagged soils, but you get the trade off of making the effort up front instead of later. You end up saving the expense of buying new plants, increase the amount of satisfaction you get from your growing experience, and you get to look at healthy, disease/insect-free plants that grow well.
Just to remind anyone listening in, the discussion isn't limited to soils. If there are other issues you'd like to discuss, feel free to comment or ask questions. I'm sure that there are others wondering the same thing(s) you are.
Does anyone have a guess as to what plant this bonsai I'm working on is? Hint: It's not a tree.
Oh My Gosh!!! That is Sooo Awesome. To take an ordinary plant that would grow and flourish without much help and to use you knowledge of soil,water,nutrients and light to make it more than just a snapdragon. That is really something.
Reminds me of the parable of the sower in Luke 8
Thanks, guys. You can do things like that with many other plants, too. I often grow Coleus, many herbs, Impatiens, ... into bonsai shapes in 1-2 growing seasons. It's fun. Which leads me to say that there really is no reason you have to accept the way your plants grow. Often we buy a plant with the goal in mind we want it to "grow big", but then what? In my travels, I'm in peoples homes every day doing estimates (I own a glass company). I get to see their plants. Very rarely do I see a plant that has been pruned or pinched properly. I think our focus would be better if it was centered on keeping the plant healthy and appealing to the eye, with a heavy emphasis on healthy. In order to do that, as in any undertaking we wish to do well, we might need to make an extra effort. I very often note that what's best for the plant and grower convenience are often mutually exclusive. You can take the approach that 'I'm going to plant this plant in something I can buy inexpensively' or you can make the effort to find the ingredients and make a soil that really will make a very big difference in your abilities to keep plants happy.
I grow under lights in the winter, with most of my plants being in much smaller volumes of soil than what most of you are used to, and I water most plants every 3 days. Because the gritty mix holds very little water BETWEEN the particles (almost all of it's water retention comes from the water held in internal particle pores) you need to water more often. THAT, is a good thing. When you water, it forces unhealthy gases from the soil and pulls fresh air in. The gritty mix already has excellent gas exchange (probably a new term for most) because of its high porosity, but the extra waterings regularly flushes CO2, methane, and sulfurous gasses that tend to accumulate in heavier soils that hold perched water. These heavier soils produce a considerably larger volume of these gasses than soils with greater air porosity, too.
Hello..It's me again. I don't know about anyone else but I would love a run down on fertilizers. I've bought every kind there is. I seem to remember you explained fertilizer on another thread but can't find it...
Ok - Soil structure will probably have the most significant impact on your success; that is to say, on your ability to consistently produce healthy plants that grow well. Light is very important, too, but there isn't much you can do about light, other than supplement it or move plants to where light levels are most appropriate. As important as light is, it usually gets short shrift for the reason stated. Nutrition is very important, too. I covered the basics in the OP, so if there are questions after reviewing it, please feel free to ask.
With CRFs (controlled release fertilizers) the water-soluble fertilizers many of you are accustomed to have been modified to slow the release characteristics of the nutrients. There is no official differentiation between slow-release and controlled-release fertilizers,
but we can make a simple differentiation. The granule fertilizers we often use on our lawns & gardens are 'slow release'; because they have polymer chains that are gradually broken off by microbes & made available for roots to uptake. Moisture, time, and microbial populations drive availability of these granular & marginally soluble fertilizers.
The term 'controlled release' fertilizer (CRF) should be reserved for fertilizers that are encapsulated or coated. Just think of a Tootsie Pop sucker, with an outer coating of candy and the good stuff inside. CRFs are much the same, with the trick being how to get the good stuff to pass through the coating so plants can take it up.
That's made to work by making the coating permeable. That means water can pass through, and it DOES pass through because water is attracted to salts. When the water passes into the prills (pellets) some of the nutrients are dissolved. How much can be dissolved is controlled by the TEMPERATURE. If the Tootsie Pop was in a cold refrigerator, the Tootsie Roll center would be reluctant to dissolve, but as it gets warmer (like when you suck on a Tootsie Roll for a while) it starts to dissolve. This is what drives the release of nutrients in CRFs. By varying the coating thickness, the interval over which the nutrients are released can be varied - 3 month, 4 month, 6 month, 9 month, are all popular formulations.
I prefer soluble fertilizers like Miracle-Gro, Peter's, Jack's, others. My Favorite is Foliage-Pro 9-3-6. It is a 3:1:2 RATIO fertilizer, so it comes closest to supplying nutrients in the same ratio plants use them, a decided plus (review the initial post for more). They give you much greater control than either CRFs or slow release fertilizers. Try to avoid any fertilizers that have a middle number higher than the first or third numbers. They supply much more P(hosphorous) than the plant can use. In a recent conversation with the CEO of one of the companies I just listed, he confirmed the lack of need for 'special' fertilizers for practically any plant you might grow, citing the 3:1:2 ratio fertilizers as being what should be the 'go to' fertilizer for practically all plants. We also discussed the folly in using fertilizers (in containers) that often supply up to 30X the P a plant could ever use (as in the commonly seen "bloom-boosting" formulation 10-52-10), indicating that the only reason for producing them was that people have been tricked into using them, and if they aren't produced they lose market share.
The best all purpose fertilizer I've found is Foliage-Pro 9-3-6. It supplies ALL nutrients essential to normal growth in the ratio used by plants (on average), and it derives about 2/3 of it's Nitrogen from nitrate sources. This is a plus for any plants grown in low light because nitrate N helps to keep internodes (the distance between leaves) short, so plants look fuller & don't get as leggy. My second choice would be Miracle-Gro 12-4-8 in liquid form (because it's so easy to mix & use), then any brand of granular soluble fertilizer in 24-8-16. MG, Schultz, Peters, Jacks ... all make 24-8-16. All these fertilizers listed have 3:1:2 RATIOS, even though the NPK %s are very different. It's the RATIO that is most important - not the NPK %s. Review the OP for more.
Thank you, Al. You've given a lot of very good basic information. I'd like to share your findings with the Nightbloomers, the evening branch of the Cocoa Beach Garden Club. May I have your permission to copy and print out your Overview for beginners?
SM - what are the NPK %s of the MG you are using. You'll find it in small print on the side of the box. If it's 24-8-16, or if it's in a yellow jug it will be 12-4-8. If you're using 20-20-20 or other NPK formulations, you could do better. If you're using any of their formulations with P as the highest number (middle number), I'd suggest you switch to 24-8-16 or 12-4-8.
Mittsy - I'm often asked by club representatives & authors for permission to use things I've written in newsletters or other work. I always say yes, but do ask that I'm credited: first/last name, city/state, email addy. Just send a D-mail & I'll provide the info. I'm flattered that you found enough value in what I said to want to share. Thank you.
I'm glad you showed a picture of the medium you use because turface comes in two sizes. One is a powdery mix and the other is larger. I'm getting the larger assuming the thats what in the picture, I am also getting some vermiculite to add.
Yes - if you want Turface, ask for 'Turface MVP' or from John Deere dealers it's packaged as 'Turface Allsport'. Vermiculite lacks structural stability, something I'm trying very hard to impress the importance of on thread followers. It's very water retentive and breaks down into small particles easily. I use a wide variety of ingredients for soils, but almost never use vermiculite. I have a 3 cu ft bag that is 15 years old & still more than 3/4 full. In almost all cases, perlite is more appropriate for container media.
I was looking up the 'Turface', specifically where I could find it in my area. I ended up on the turface website, looking at a spec sheet. Not to say I'd want to substitute, but it looks very similar to a floor absorbent, correct?
Linda - Some floor absorbents can be substituted, if the size is appropriate and the material has been fired at high enough temps that they're stable. To test, freeze them in a plastic class or dish overnight. Thaw the next day & see if they retain their structure. Some floor absorbents are calcined (fired at high temps) diatomaceous earth, and some, like Turface are calcined Montmorillonite clay. When the topic is container soils, size is important. Ideal for the gritty mix are particles in the 1/8" size range, with the bark being a little larger @ 1/8-1/4 or so. For the 5:1:1 mix, the bark should be from dust size to about 3/8".
Try the John Deere dealer @ 385 Crosspoint Pkwy in Getzville [(716) 568-1440] for Turface Allsport. If you're interested, you should be able to find Gran-I-Grit crushed granite in grower size at elevators or feed stores catering to those with farm animals, but not the big box stores.
I find many of the growers I talk to decide they'd like to start growing in soils like I use, and I think that's great. If you happen to be struggling in your ability to keep your plants happy, deciding to change to a more open soil (one with superior drainage/aeration) is probably the singular decision most likely to result in significant progress. I also find that often, growers get really excited about the recipes and in a hurry to get started. If you go about it at your own pace, you're much less likely to get frustrated if you can't find things. Late fall and early winter aren't the easiest seasons to find pine bark of a favorable size, but I think that's where you should start your search. That way, even if the Turface and grit are elusive, you can always fall back on the bark-based mix I posted a picture of in my first post 10/29 upthread. They're both excellent soils for houseplants, and I use the 5:1:1 bark-based mix for all my mixed container plantings scattered through the gardens & on the decks.
I guess I would hope that you don't get frustrated too quickly and that you don't lose site of the fact that I'm selling (that is, recommending) a concept rather than recipes. The recipes are simply the best ways I've discovered to implement the concept.
I am planning on finishing up with what I have before purchasing more. A friend gave me about 5 lbs. of potash this summer. I have been adding it to the bottom of my container pots before adding in soil. It's still too early to decide whether or not this helped.
I also have azelea ferterlizer and am reluctant to use it since I don't have azeleas. I do have one camilia that I spinkle lightly with it though.
Hate to see it wasted.
I have spent the last few days reading and taking notes on all the information you have given here.I was noticing in your pictures you grow succulent and cactus.How does the fertilizer change for them? Most cactus-succulent fertilizer is something like 2-7-7.
The plants in your pictures are just beautiful !!!
Peg - I talked upthread about the importance of following a good nutritional supplementation program. I'm not sure if it was on this thread or somewhere else where I cautioned against using a little of this and a little of that because someone thinks it might work. Far more often than not, those elements or compounds aimed at supplying a singular nutrient (in your case with the potash it's K [potassium]) end up being a limiting factor, rather than a benefit. If your plants don't exhibit recognizable symptoms of an actual K deficiency, adding the extra potash is going to unnecessarily contribute to what is dissolved in the soil solution. The more there is dissolved in the soil solution, the harder it is for plants to absorb water and nutrients. PLUS, if you have WAY too much potash (which isn't hard to do) it can cause antagonistic deficiencies of other nutrients.
What makes a fertilizer appropriate for various plants doesn't have anything to do with what's ON the box (label). It's the NPK %s and the ratio of nutrients to each other that determines what's appropriate. There is nothing special in azalea fertilizer that makes it particularly good for azaleas. It's probably 30-10-10 with urea as the nitrogen source so the urea can produce an acid reaction as it breaks down.
Hi, Jo - thanks for the kind words. Who says that cacti or succulents prefer 2-7-7 or something similar? (I'm smiling - not being confrontational - sort of a poke in the ribs.) They USE nutrients in about the same ratio as other plants, so it's difficult to envision how someone could make a case for providing nutrients in a ratio other than that which they use. We know that plants use about 6X more N than P, and about 3/5 as much K as N ... this is on average, but the range of variation is very small.
I gave Nitrogen, because it is the largest nutrient component, the value of 100. Other nutrients are listed as a weight percentage of N.
P 13-19 (16) 1/6
K 45-80 (62) 3/5
S 6-9 (8) 1/12
Mg 5-15 (10) 1/10
Ca 5-15 (10) 1/10
To read the chart: P - plants use 13-19 parts of P or an average of about 16 parts for every 100 parts of N, or 6 times more N than P. Plants use about 45-80 parts of K or an average of about 62 parts for every 100 parts of N, or about 3/5 as much K as N, and so on.
If we use 2-7-7 as an example, we know that because all plants use about 6X more N than P, that 2-7-7 supplies about 10.5X as much P as the plant can use relative to N, and more than 5X as much K. As I mentioned to Peg earlier in this post, and because we all fertilize as a function of the plant's N needs, the excess P and K will unnecessarily contribute to what is dissolved in the soil solution. The more there is dissolved in the soil solution, the harder it is for plants to absorb water and nutrients.
It's only when I'm intentionally trying to manipulate a plants growth habit that I use a fertilizer OTHER than one in a 3:1:2 ratio, and that is for ALL my plants. For review, 3:1:2 ratio fertilizers include 24-8-16, 12-4-8, 9-3-6, and a fertilizers RATIO of nutrients to each other is far more important to sound nutrition than its NPK %s.
I think there are not many ways to become a good grower. The best way, is by paying your dues and gaining a good understanding of the intricacies of how plants grow and interact culturally with their surroundings. That takes time. In the meanwhile, new growers can advance in their abilities very quickly by following the direction of someone who does understand some of the intricacies. This may not make a new grower proficient in the true sense of the word, but it can help circumvent a lot of initial frustration and increase the satisfaction:effort quotient while in the process of refining understanding.
All of the information you need to be an accomplished container grower fits together like a jigsaw puzzle that is under assembly. Each of the pieces are somehow connected to the other pieces - either directly or extraneously, but they ARE all connected. If ever you’ve put a jigsaw puzzle together, you probably remember that it’s easier when you try to get the outer 'frame' together first. This outer frame is representative of an understanding of the most basic knowledge that is needed for success. Of the basic knowledge, most important is an understanding of how the soil/water relationship works & how the individual soil components interact as they relate to the whole. Basically we need to understand that a healthy root system is required if the plant is to be healthy. Then, and easier to understand are a very few additional issues like the importance of light to your growing experience, how fertilizers work and what fertilizer is most appropriate ……. We also need at least a very basic understanding of how some of the other cultural conditions might affect plant growth/performance. Once the grower has this essential understanding in grasp, that is to say the framework of the growing puzzle completed, assembling the rest of the pieces will occur at a rate exponentially faster than the rate at which you progressed at the outset of your growing experience. Unless this basic framework is complete, we’re basically relying on trial & error, which is certainly no short cut to success.
Thank you once again for clarifying fertilizers for us. Guess I should take an inventory of what I have and begin there. Please throw in any additional information and feed our minds. This opens so many doors.
Ohh, thanks! You guys are very kind. As you have questions or comments, I'll be glad to add my comments or answer to the best of my ability ... and I'll try to keep things as easy to understand as possible. My hope is that, together, we might help you isolate and eliminate some of the factors that are limiting, while providing an understanding of what actually makes them limiting.
Thanks so much for the answers and information Al,
We have been discussing "store bought fertilizer, what about natural things? I have a large worm bed that I use the top portion of as "mulch" to cover beds & put under bushes during the winter.Not the worm castings but the stuff that's not completely broken down,we also till it into the ground when making a new bed.
Then there is the worm casting's, I've been told it's good for anything and I have mixed it into some potting mediums while making them.I have a friend who comes and gets worm castings & she uses it in all of her plants inside and out.
I was also given a product it's labeled on the box "kricket krap" it's labeled as being 3-2-1.What if anything could I use the latter for and what are your thoughts on worm castings?
We recently moved onto a piece of property and if I rake back freshly fallen leaves "last few years" there is what I call natures own compost.Any thoughts on uses for that?
thanks for sharing all the beautifully interesting pictures and how did you manage the last teeny tiny one?
Good question and a good opportunity for me to go a little deeper into why your choice of soils, and particularly their structure is so important to the o/a health of the planting.
I think the most important part of the message carried in this thread is that if you provide a soil that starts out as a well-aerated medium and stays that way for the life of the planting or at least the interval between repots (as opposed to just potting up), you'll have done yourself a considerable favor that will be manifest in your ability to consistently produce healthy greenery. There is a stark difference between growing in the garden and growing in containers. On a scale of 1-10, with 1 being growing in the garden and 10 being full scale hydroponic growing, container culture is probably about a 7 or 8. IOW, container culture is MUCH closer to hydroponics than it is to growing in the earth, so it shouldn't be a surprise that much of what works well and holds true in the garden, DOESN'T work well and can even be counter-productive in containers.
I think there are actually two points in your question that need to be addressed. One is, 'what do these organic soil amendments do to the soil's structure, something I think should be judiciously watched over'? The other is, 'what do/can they provide and how effective are they/can they be'?
From the structural perspective, growing in soils comprised of fine particles (peat, compost, coir, sand, topsoil ...) already presents a significant set of problems described at length above, so for best results, we would want to shy away from those soils whenever possible. Adding even more fine ingredients to your soils, like worm castings; manure, which breaks down quickly; vermipost; various meals designed to to deliver nutrients - hoof/feather/bone/horn/cottonseed/alfalfa meals ...; all add to the problem of increasing water retention and decreasing aeration in a soil that is probably already too water retentive from the outset.
From the nutritional perspective, there just is no way to make nutrients available to plants in anything resembling a favorable ratio and on schedule (so WE know what is actually available, and when) than via soluble synthetic fertilizers. It is immeasurably easier and more effective.
Before I explain, I'm going to say that I am results driven. I don't care about ideological or political arguments against soluble fertilizers. If a person wants to self-limit by allowing politics or personal ideology to take precedence over what is most efficient and best for the plant, I won't argue the point, but I will debate the issue from the perspective of what works best and most efficiently.
Using organic soil amendments in containers is fraught with uncertainty. Plants cannot absorb nutrients locked in large molecules that make up the even larger hydrocarbon chains that must first be cleaved by soil biota (soil life) before the nutrients can be reduced to an elemental form plants can take up. The problem with this scenario is that soil biota populations and activity levels fluctuate dramatically in containers. Since we depend on their numbers AND activity, their ability to make nutrients from organic sources available is very erratic. What you apply today in the form of organic soil amendments may not be available for weeks. The term 'organic soil amendments' also includes fertilizers that derive nutrients from organic sources, as that term more accurately describes them.
In comparison, when you apply a soluble synthetic fertilizer, like Foliage-Pro 9-3-6, you can be sure you're supplying nutrients that are immediately available for uptake, in the same ratio in which plants use them, and you know exactly how much is available. It doesn't get any easier. I noted there is a technical difference between a fertilizer (Miracle-Gro) and a soil amendment (feather meal), but even that point eventually becomes moot from a strictly nutritional perspective. Plants take up elements that are dissolved in the soil solution and in ionic form. What they take up are salts. As noted, the large molecules that make up hydrocarbon chains in organic fertilizers/soil amendments cannot be taken up by the plant unless the hydrocarbon chains are broken down into elemental, soluble form by soil organisms. At that point, the elements from soluble fertilizers are exactly the same as the elements from organic sources, which is why the plant could care less. At the point in time where nutrients are assimilated by plants, they are ALL soluble and in elemental form, regardless of whether they came from a dead fish, compost or a hose-end sprayer.
I'm all for easy and uncomplicated. Nutritionally, you can hardly go wrong using a 3:1:2 ratio fertilizer like MG 24-8-16 or 12-4-8, or my favorite, Foliage-Pro 9-3-6.
Thanks again to all for the kind words. The little Portulacaria afra (mini jade) is a cutting from its dad in the picture above. I saw a plant in a thimble once, which gave me the acorn idea. To grow it, I drilled a hole in the bottom of the acorn after filing the bottom flat so it would be stable. It sets in a jar top on a paper towel under lights. I water it every night with distilled water from an eye dropper, and fertilize occasionally. The acorn lasts about a year before it rots & the roots break it up.
I was a little late getting into this conversation of information ! So I have a question that goes back to a post or 2 that you talk about your potting medium that you use and where you show pictures of your mixture.I was looking at the mixture and you said one of the important things is the size of the particles in it.
My question is what is the importance of what those particles are example: broken up pieces of terra cotta from old broken pots.(instead of crushed granite) If they are broken down into the right size are they just as effective to use.Especially if some kind of peat is being used which holds water and Terra Cotta draws out water
I'm the student in the class that will drive the teacher crazy with questions.But it's because I'm interested and want to understand your way of doing things,To successfully compare what other people think to have an informed idea on what works and what doesn't.There are a lot of theories out there!
Including my favorite plants (hoya's) like to and grow better being root bound.I've never let a plant get root bound & I always trim roots.
Ok I'm finished haha hope your day is pleasant
Great questions - looking forward to answering when I have more time. Heading to work & trying to deal with a kitten that likes to walk on the keyboard for some reason. ;-)
I will say though that there are a lot of beliefs and theories that don't hold up under even casual scrutiny. One of my favorite quotes is, "The destroyer of weeds, thistles and thorns is a benefactor, whether he soweth grain or not." ~Robert Ingersoll
In some cases, dispelling horticultural myths is as much as favor as lighting the most productive paths. I'll be back later. ;-)
Making my way through fact and myth is something I've been trying to do.But trial and error isn't the best way to do it.I don't have a plant I am willing to sacrifice to see if something will or won't hurt it.Your info. seems to come with as close to proof as I've ever seen any where.
I didn't come by the information I'm sharing by trial and error because I too, recognized the futility in trying to progress at anything other than a snail's pace with trial and error in place as my only way of assimilating knowledge. There is just SOOO much going on with plants that you can't see, that it's virtually required that you have a good understanding of how plants and the associated sciences work to become truly proficient. Yes, growing is supposed to be fun, but it's also supposed to be rewarding. Unconsciously, we all seek balance in our devotion to our pastimes. Some are perfectly content to buy plants as others of theirs die, in a sort of 'revolving door' plant policy. I think most, my self included, get greater satisfaction from their ability to nurture plants and keep them healthy over the long term.
I was at a business meeting in Chicago about 25 years ago. I was bored and wandering the halls of the building on a Thu night when I discovered there was a bonsai show being set up. I was granted permission to watch, and I was immediately enthralled with the little trees in diminutive pots. I knew right then, that I HAD to learn how to create the beautiful works of art that were their little trees that looked like something just plucked from the meadow or mountainside. I went home & tried my best within the limits of my nonexistent skill set. After failing miserably because I couldn't keep my trees alive, and with no one to guide me, I set the trees aside and started studying. I learned after a while that soil science and physiology were basic requirements if I was ever to become proficient. I studied diligently for about 4 years before I felt I had enough basic knowledge to keep my plants alive and healthy.
I learned early on that your soil is the foundation of your plantings, and if you don't get the soil right, you'll be fighting it for the entire life of the planting. If you DO get the soil right, you eliminate (easily) 90% of the issues people come to this forum asking remedial help for. Almost everything I know about plants has come as an offshoot of my 25 year pursuit of proficiency at bonsai. You can see by the pictures that I have no problem keeping a wide variety of plant material healthy and attractive. It's EASY - honest; ... as easy as a good soil, good light, good nutritional supplementation, and good watering habits. I know I can give you everything you need except the light. Several years ago, I would never allow myself the boldness to make that statement, but I have helped so many thousands to understand what it takes to be proficient at container culture, that I now feel perfectly comfortable putting myself out on THAT limb. ;-)
I usually don't spend a lot of time trying to convince anyone that I know my stuff, preferring to let the reader's perception of how everything seems to fit together perfectly make the impression. I mentioned that I was recently invited to a botanic garden affiliated with U of M to address a group of specialty growers. We talked mostly about soils, but about nutrition and other aspects of container culture as well. These were people well advanced in their education, many of them degreed in horticulture or related fields, many currently making a living in fields related to growing. There were no raised eyebrows or signs that anyone dissented with anything I offered, and the question/answer period after the presentation lasted more than twice as long as the 1 hour presentation itself. Hopefully this knowledge and the fact that I'm very often invited to address groups & clubs on a wide variety of topics will ease any anxiety you have about putting anything I say to practical use.
Your original question was about particle size and what makes the material the particles are made of important.
Particle size is important because it is usually the primary factor determining water retention. Internal porosity plays a part in the equation, but I'll get to that in a sec. We know that if the particle size is too small, that your soil holds perched water ... and perched water kills roots - period. If particle size is too large (think of a jar of marbles), there will be so much air space that water retention will be reduced to what might be a level that requires the inconvenience of having to water more often than you're willing to. Now, a soil of ALL large particles can be VERY productive, but most aren't willing to water twice per day or more often - and it's unnecessary.
The balance point then, in particle size, seems to be at about where any perched water disappears from the soil. Fortunately, we know that perched water disappears as uniform particle size approaches that 1/10-1/8" size. A large fraction of smaller particles ensures perched water the volume of which increases as particle size decreases, and too many larger particles reduces water retention with little gain - primarily a convenience issue. So, it makes good sense to keep the particle size just a little larger than what it takes to support perched water - this maximizes water retention without suffering the consequences of a perched water table.
For those that are going cross-eyed at the technical nature of the conversation, just take from this that your soils need to be made of PRIMARILY larger particles, like pine bark, to actually realize the benefits of a soil with a reduced PWT height. This is the key issue from which most growing difficulties radiate. You can't take a peat-based soil and add bark or perlite to it and make it drain well or significantly reduce the ht of the PWT. Before anyone disagrees with this, think of a quart of pudding. Will adding an equal measure of perlite or pine bark to it increase aeration or make it drain well? NO, it won't. It's only when the perlite/bark fraction becomes 80% or MORE of the whole that we get and benefit from the larger particles in terms of aeration and drainage. The fine particles simply surround the larger particles & not much changes ... which is why I urge growers that really want improvement to get moving & find a suitable source of pine bark, or develop a soil that is comprised of larger particles. You simply cannot expect to realize the results using soils based on peat, compost, coir, topsoil, sand, or other fine ingredients as you can with the more open soils with better aeration.
Back to your question: What the particles are made FROM, is only important from the perspective of water retention. You can grow perfectly healthy plants in crushed glass if you want to, but it doesn't hold water worth a darn and has virtually no CEC (doesn't hold nutrients well). Ideally, you'll have a soil comprised of suitably sized particles that hold MOST of their water inside the particles, leaving the spaces between particles large enough that they can't hold water and remain air-filled. Pine bark fits that bill nicely as the primary fraction of the 5:1:1 mix, as well as a fraction of the gritty mix. As noted above, Turface has tremendous internal porosity (14 acres of surface area per pound, which also endows it with excellent CEC [ability to hold nutrients]), so it holds lots of water. Combining it with the bark and crushed granite, the granite being devoid of any internal porosity, offers the grower a simple way of adjusting water retention by simply varying the ratio of Turface:granite while keeping the bark fraction at 1/3 or less.
It's hard to let go of the idea we need a rich black soil for our houseplants, but we really don't. If you give it a try, you'll find the gritty mix or even the 5:1:1 mix is much easier to grow in and much more productive.
I get asked that question a lot! It's a begonia with a rather inconspicuous bloom, but a wonderful, almost neon burgundy leaf margins. I look for it every year, but only occasionally find it. Sorry I can't name the cultivar.
Scroll upthread to my post of Oct 29 for a picture of appropriate size pine bark. If you have trouble keeping the Begonia happy, it's almost a certainty it's not because you used MG fertilizer - unless perhaps you were using one of the 'bloom booster' formulas, which can be a problem. I use nothing but soluble synthetic fertilizers (like Miracle-Gro) in 3:1:2 ratios for everything I grow in containers - with very good results, as you can see.
I use sieves I made to screen things. Usually, I'm able to find bark for the 5:1:1 mix that doesn't need screening - like you see in the picture I mentioned. If you were going to use it in the gritty mix, it should be screened to a size between 1/8-3/8, with 1/8-1/4 being better. I'm lucky to be able to buy pre screened fir bark in 1/8-1/4 in 3 cu ft bags from an orchid supply house.
Just thought I would share that you can not chop orchid bark in a Cuisinart. As soon as we get the shredder/mulcher repaired (threw a rod) I'm going to try putting my bag of orchid bark through a few times.
If I am not being too forward, would you share with us the orchid supply house you use especially if it has the micro-nutrients.
I am having a hard time finding turface, gypsum and your favorite Flo Pro (spelling?"?)
You can get Turface Allsport at the John Deere Landscapes dealer at 11148 Cloverland Ave in Baton Rouge (225) 293-6400 or the Ewing Irrigation Stores in Baton Rouge or Lafayette, or Chastant Brothers in Lafayette (337) 234-2351. You might be able to find an orchid supply house near you for fir bark. I get mine at Oakhill Gardens near Chicago whenever I visit the city. http://www.oakhillgardens.com They also sell Foliage-Pro 9-3-6. If you use the Foliage-Pro, you won't need any gypsum (as a Ca source) in the gritty mix.
I have a small pond and am wondering about soil to use in prefab ponds. I have tried pine bark and found it floats. I have also tried the aquatic rocks and aggregate, but am not completely pleased. Please recommend a soil for pond plants.
Aquaculture is probably a little OT, but I know that Schultz either still does or has packaged Turface MVP and labeled it as 'Schultz Aquatic Soil'. Others have used Haydite, pumice (lava rock), and various other forms of calcined clays (like Turface) or calcined DE. All aquatic soils need to do is provide adequate anchorage and some water movement through the medium.
Am I the only one having a tough time finding the ingredients for the 'gritty mix'? I know I can find the chicken grit, because I have chickens... but the other two.. I have bark for my orchids, but of course they are larger pieces.
Sometimes finding the ingredients initially is the most difficult part. For Turface Allsport, try the John Deere Landscapes dealer @ 2200 Lovell in Nashville, (865) 693-3013 - or the one @ 1337 E Weisgarber Rd in Knoxville (865) 584-3566. Look for pine bark fines, soil conditioner, landscape mulch ... The size of the bark is what's most important. You want a product that looks like one of those in the picture upthread (10/29).
Tapla, do you create those frogs? I just love them. I paint frogs and turtles on rocks.
I am getting Turface MVP (14.99 for 50 lbs) today and lime. Having a hard time finding Foliage-Pro locally so I will use the lime for now. This weekend I plan on screening pine bark and turface. I think I have spagnum peat and will use Osmacote 19-6-12 on hand for my CFR which is the closest to the 9-3-6 ratio recommended.
OK, when I gather all ingredients I will get back with you, probably after the weekend.
In the meantime, I plan on screening the Turface. With the Turface fines, I will plant my seeds in flats.
Thanks for guiding me along. I have know for years that my soil wasn't up to par, but didn't know what to do. My container plants (lantana, ornamental sweet potato, coleus) in full sun were dying even though I was watering daily.
I was using Miracle Grow soil, but found the last year or two that it was inferior to prior year's soil. I began mixing peat with it, but now know it should have been spaghnum peat.
I watered occassionally with Miracle Grow or Epsom Salt ( 1 tbsp to 1 gallon of water). I found the Epsom Salt helped with the coloring of the leaves, but didn't know how often I could use it.
I have a misting system that I plan on setting up for next summer which will help when i go on vacation.
Things will improve with a little skill and effort. I belong to the local Master Gardener's Club, but soils were not touched upon during class, but now I am building my skills with soils thanks to you. It's easy to just buy the best pre-packaged soil, but knowing what is needed or required is gratifying.
Your seed flats want a very open (porous)/well-aerated soil, not something as water-retentive as Turface fines. Roots LOVE lots of air surrounding them. I would be thinking something like the 5:1:1 mix for seeds.
MG soils are already very water retentive and contain a very high % of sphagnum peat, so there really is nothing to be gained by adding more peat; in fact, it's more likely to be counterproductive than a benefit.
Whenever you add anything to your soil that is intended to supply singular nutrients, like in the case of Epsom salts where Mg is the target nutrient, it's more likely to be a negative than a positive. Epsom salts (MgSO4) supply magnesium (Mg) and sulfur (S). Sulfur is only very rarely deficient in soils, which leaves us with the assumption that any benefit derived from Epsom salts would come in the form of its Mg content. The question that needs to be asked before you use Epsom salts is, "What leads me to think I have a Mg deficiency?" If you don't have an answer or a reason to apply something, especially when it's an element or compound targeted at increasing the amount of a singular nutrient, you're better to forgo the application; because if it's (magnesium) not deficient, more can't possibly help; rather, it will be a limiting factor.
The basic recipe for the 5:1:1 mix calls only for garden (dolomitic) lime. It's used as a pH adjuster and as a source of Ca/Mg in almost all commercially prepared soils, too. Because the pH of the gritty mix is considerably higher to start with than the 5:1:1 mix, you would only use gypsum as a Ca source in it (the gritty mix) because it doesn't impact pH measurably. Once you decide on what you want to use insofar as the soil goes, let me know and I'll help you with the best way to go at it, and I'll explain exactly why it's best to take that particular approach. I can go as deep as we need to in explaining, but for now I'll try to keep it simple.
I should say too, that it's not really any more complicated to grow in any of the soils I use, it's just that you're being introduced to concepts that most beginners have never been exposed to or considered before. The same considerations are actually in play for all soils, it's just that most of you have probably never applied them before.
1 part screened pine or fir bark
1 part screened Turface Allsport or MPV
1 part crushed granite or cherrystone (Gran-I-Grit in grower size or #2 cherrystone)
What you use as a fertilizer with the gritty mix determines whether or not you should add Gypsum as a Ca source and use Epsom salts as your magnesium source. If you just go with the Foliage-Pro 9-3-6, you don't need to add anything else to the soil. It's one of the few soluble fertilizers that contains Ca and Mg.
I'm not sure where the middle recipe came from. If I posted it, I was because I was helping someone address a specific issue. The gritty mix contains no small particles, as that would defeat the purpose - a root-friendly long-lasting soil with good water retention (w/o supporting perched water) and superlative aeration.
It's important that bulbs have excellent drainage. And BTW, "drainage layers" don't improve drainage, they simply raise the saturated layer of soil higher in the container. Ask if you want that explained in detail. Either of the soiuls I use wouyld be very good for bulbs.
I use either the gritty mix or the 5:1:1 mix for all my plants. The way I decide which to use depends on my answer to the question, "Will this plant be in the same soil for more than a single growth cycle. If the answer is 'YES', I opt for the gritty mix. If the answer is 'NO', the 5:1:1 mix is the soil of choice. I grow all my veggies and the mixed display containers that are scattered around the gardens & decks in the 5:1:1 mix because they are only going to be around for a summer. Everything else, including all my houseplants and all the trees that either ARE bonsai or are being grown on as potential bonsai.
I should note though, that I'm probably a little more particular about guarding against the collapse (breakdown) of soils. Just because I usually only keep plants in the 5:1:1 bark-based soil for 1 year, doesn't mean that that particular soil breaks down quickly. In fact, on a size for size basis, conifer bark breaks down at about 1/4 the rate of peat's breakdown. When you add in the fact that the particles are larger to begin with, you can easily see that the bark based soils will remain serviceable for MANY times (5-8?) times longer than soils based on fine organic particulates like peat/coir/compost. In virtually every case, root-bound conditions becomes a primary limiting factor long before soil collapse could/would.
Moving way back to the top of the thread, I mentioned how important regular root work is to keeping your plants healthy and growing well. 'Potting up' won't do it - repotting and its accompanying root pruning and changing of the soil will. I'm not sure why you never read about this in plant books, but you only need to look to bonsai trees to see the validity in what I'm saying. Bonsai trees are often maintained in tip top health for many hundreds of years, while most of us have great difficulty keeping plants healthy for just a few years. Since many of the trees we grow as bonsai are the same trees we might grow as houseplants, an answer is begged to the question, "Why the difference?" The difference is in the root work.
In nature, plants' larger roots serve only as anchors so the plant doesn't blow over, and as conductive plumbing. The plant really doesn't need them because all they really do is take up space that COULD be occupied by the fine roots that do all the work. I'm getting away from your question now, so I'll leave you with the reminder that after you get the soil right, regular rootwork is a very important part of maintaining your long term plantings, like houseplants.
What you may have run into is a JD dealer that doesn't want to order a pallet of it at this time of year because he doesn't sell enough to warrant stocking the remainder through the winter. I've had some difficulty getting the JD dealer near me to order it for me, too ... unless it coincides with when there s a lot of activity going on with people building ball diamonds or redoing sports projects/athletic fields where the Allsport is so often used for it's drainage/aeration enhancing properties.
JJ - I think that one point that almost all container gardeners are stuck on is that the soil somehow has to be the source of the nutrients. So often we get excited over rich and black soils because we know thing usually grow well in that type of garden soil, but water behaves much differently in garden soils than it does in containers. To answer your question ... I haven't grown anything in a commercially prepared, peat-based potting soil for more than 20 years. What I make and help others to make is soo much better and less expensive, it makes no sense for me to use commercial soils. The only reason I could think of to use a commercially prepared, peat-based soil is if you didn't understand the importance of good drainage and aeration, or put another way - if you didn't understand the negative impact of excess water retention; AND, you placed a lot of value on convenience - on the fact that you can just buy the soil and have a plant in it 15 minutes later w/o having to actually make it yourself.
When it comes to nutrition, the best thing a results oriented container gardener can do is shoulder the entire burden of ensuring his pl;ants get all the nutrients they need and that the nutrients are always available in a favorable ratio and at a favorable concentration. By far, this is easiest to achieve through the use of soluble synthetic fertilizers. I have nothing against organic sources of nutrients, and I depend on them almost exclusively in the gardens & beds, but when it comes to container culture I find it difficult to conceive of how effective nutritional supplementation could be any easier or efficient than with soluble synthetics. Combining them with a durable and well aerated soil is getting pretty close to foolproof.
If you scroll up to the picture I posted on 10/29, you'll see pine bark fines from 3 different sources. You'll usually find the product labeled as something other than pine bark fines - pine bark mulch, soil conditioner, landscape mulch, others. The important thing is that most of the particles are in the size range of dust to 3/8" for the 5:1:1 mix, or screenable to 1/8 - 3/8 for the gritty mix.
Just so we're clear - I don't make any judgment about an individual when it comes to discussing what people choose to grow their plants in because I haven't walked a mile in their shoes & would never suppose to order someone else's priorities, but judging a soil is quite different from judging a person. It is very often possible and in some cases easy to make judgments about practices or soils, and to compare soils based on science. My aim is to lay out the information people need to become more proficient at growing and to gain greater satisfaction from the experience. I fully realize I have no control over other people's choices, and don't want it. I do get a lot of satisfaction though, from being associated with people who DO want to learn and who will put forth the little bit of extra effort it takes to shrug off the limitations that are inherent in heavy soils and practices that make little hort sense. ;-)
You nipped my problem in the bud.I was looking for something that was right in front of me,but I didn't understand about the labeling.I guess I'm not up to speed on the language of gardeners.I have tried to make a soil-less potting medium,rather I am following your instruction here trying to improve my own skills.There's always room for improvement my moma used to say and the only dumb question is the one not asked.I am fairly new at this,I took up house plants as a hobby when I was diagnosed with MS,so I would like to learn as much as I can.Sorry my questions are so basic!!
I don't think anyone should ever feel embarrassed about where they are on their journey to proficiency, or about the questions they ask seeming too basic. I have much more respect for the growers who are trying to improve their abilities and increase the satisfaction they get from growing through their acquisition of knowledge, than for any who might pooh pooh science in favor of trial and error. The problem with being content with learning by trial and error is the 'content' part. Usually, if you're content with learning by trial and error, you're also content with committing the same errors over and over. Even if you don't make a change in your soils or nutritional supplementation based on what you absorb from my offerings, you will, at the very least, be able to RECOGNIZE the source of problems in the future. Because the trial and error crowd can't SEE what is going on in the root zone, and often have no way of discerning nutritional problems other than through the application of some basic science, they're at a decided disadvantage.
Don't worry about being up to speed on the language. If you come across a word or phrase that confuses you - look it up, or ask for clarification. I think you'll be amazed at what you'll learn while chasing down answers. One of the reasons I enjoy answering the more technical questions is that I'll often check to be sure my offering is technically correct. I learn a LOT when I look things up because I always read enough to make sure I understand the context.
Thank you for the kind words. I did have a very nice Thanksgiving. The kids and grand kids were here, a few friends ... even my wife's ex and his mother were here (his brother couldn't make it). ;-) We had the traditional turkey & all the fixin's. I'm also the cook around here. I've been married for 32 years and I think the number of meals my wife has had to prepare in that time could be counted on 1 hand. Our deal is I cook & she cleans up the cooking mess - but I do help by cleaning up all the prep mess as I go. I hope you and everyone else had a good holiday, and that you all found plenty to give thanks for. Musing: as I grow older, I welcome the time I often take to dwell on the things I have to be thankful for - on the 'Thanks' part of Thanksgiving. Strangely, and I focus on this often, one of the things I'm most appreciative of is the ability to be ever grateful for the countless blessings in my life. One of the things I count as a significant blessing is, the realization that happiness revolves around our ability to feel blessed by what we have, in contrast to being forever in want of what we don't have, came to me early in life. Hardly a day passes now without my reflecting on the number of things in life that bring me joy.
I agree totally about your Thanksgiving thought. I often feel it is a characteristic I aquired later in my life and try to teach my children the same. I too am thankful that I do the cooking and DH does the dishes.
Since we are having rains these days, I haven't gotten to start my soil mixture(s). Hopefully tomorrow brings back the sunshine.
I'm so glad you both had such a good thanksgiving!!
Al, you speak of your family in such a loving & appreciative way,it's so nice to hear people talk about being thankful for what they have.It seems so many don't understand the meaning of thanksgiving any more.I have learned to be happy with what the good lord has blessed me with and not dwell on what i don't have or can no longer do.My 2 daughters,2 grandsons,my plants and of course the DH keep me going and thankful that i can!!!
I have to say the picture is incredible!!
I can't wait to read more of the knowledge your so happily willing to share with us about growing plants!!
Al, I had a severely root-bound pothos plant that I root-pruned and divided into 5 smaller plants. Some of the divisions aren't looking so good... yellow and droopy. They were all transplanted into either the 5:1:1 mix or the gritty mix. The peace lily that was root pruned and transplanted is looking beautiful but requiring a lot more water than before; it droops after just 3 days.
Are you supposed to water more often after root-pruning? I'm used to using the "fingers in the soil to see how wet it is" method, but that doesn't work anymore...
Thanks for the holiday wishes. I hope too, that everyone had a good Thanksgiving - good food and good fellowship.
It's not hard to hand tame a Chickadee. I recently sold a piece of hunting property that was home to at least 50 tame Chickadees, maybe a dozen nuthatches, a few tits, and a brown creeper. They all have curiously different habits, but I'll just tell you how to hand tame the chickadees & then we have to get back on topic so future readers don't have to sort through too many OT posts.
Hang a feeder from a tree branch and fill with sunflower seeds to get the birds used to coming to the feeder. When you're ready to tame the birds, take the feeder down and put it out of sight. Put some sunflower seeds on your hat, and lean against the tree - very still. Almost immediately, the chickadees will land on your hat. Once they're used to that, shake the seeds off your hat & hold them in a gloved palm. They'll soon be eating from your hand. I can usually hand tame birds within 10 - 15 minutes, once I take down an established feeder. The farther away the nearest neighbor's feeders are, the easier it is to hand tame them. They have little incentive to eat from your hand when the neighbor's feeder is only a few wing beats away. It really is a lot of fun to go out in the back yard & spend time photographing the birds. I can get them to give me a kiss by putting a sunflower between my lips & holding my hand palm down and flat, even with my chin. They land on the hand & pluck the seed from my lips - pretty cool. ;-)
TR - I think that deeper pots are easier to grow in, and pots with gas permeable sides produce healthier plants.
If a soil supports 3-4" (ht) of perched water, it supports that ht of perched water in any container, regardless of its size or shape. If you use a heavy soil that supports 4" of perched water in a 4" deep pot, the entire soil volume remains saturated after a thorough watering; but if you use the same soil in a 12" deep pot, only 1/3 of the soil volume remains saturated. So, the shallower the container - the more important it is that the soil drains well and supports little perched water.
As far as pot material, I prefer terra cotta because it's gas permeable. It lets air in, and the undesirable gasses like sulfurous compounds, methane, and CO2, out. It's especially valuable when you're using heavy soils because the porosity speeds evaporation of the water in the soil. Reducing the amount of water over-retained much faster than pots made of nonporous materials - plastic, glazed clay, etc. Pots with mesh sides are also good, and I use a lot of cedar boxes for the material I'm growing on as future bonsai. They're not the prettiest, which is why I'd probably give terra cotta the first nod as being best for houseplants. Remember too, that I'm answering from the plant's perspective - from the perspective of what's best for the plant. While many may prefer the prettier appearance of other pots and the 'convenience' of not having to water so often. Those votes are not from the same perspective; and though they need to be acknowledged, while doing that let's acknowledge the dissimilar perspective.
SSG - just a guess, but it sounds like perhaps you got some really large bark to make your soil and it's not holding enough water? Particle size is important - let me know how big the bark was and how you made it.
You DO need to water more often after repotting if the remaining root system is small. Also, since all but winter growers (plants that tend to grow more when days are short) are wanting to rest now unless they're under very good lights, it's going to take a while for the roots to reestablish. In most of the US, the period between Father's Day and July 4th is about the best time to repot. Those in the southernmost parts of the US can repot a little earlier and still get very good results.
Can you share a picture of your soil? I think that once the PL's roots colonize the entire soil mass, your watering intervals will increase, but lets look a little deeper into what's going on.
Wow - undoubtedly one of the nicest compliments I've received. Thank you so much for the very kind words, Shoe.
I just commented on another thread that education (knowledge) is what puts us on the fast track to 'green thumb' status, not experience. If we ask ourselves the question, 'Is doing something wrong or ineffectually again and again in the same way for a half century worthy of being called experience'? - most will answer with a resounding 'no'. Knowledge is key because w/o it we have no way of knowing when we're doing something wrong, or when our efforts are less effective than they could be. Too often we make up science to fit our observations, instead of questioning our observations when they don't fit with what we know of science. Getting the basics right so we CAN question our observations and not mistakenly adopt them as dogma is the reason for my starting this thread. My hope is that everyone that follows it will end up with an improved growing experience through better understanding.
It doesn't matter what you use to measure the ingredients. The measurements are by volume, so a cup, a gallon, or a 5 gallon pail of each will yield the same soil. I keep several bushels of screened ingredients on hand at all times so I can make any size batch I want. With around 200 bonsai, most requiring yearly repotting, plus all my other plants, you can see that I go through a LOT of soil. I usually add about 2 gallons of each ingredient to a masonry mixing trough, mix thoroughly, pour the mixed soil into a trash can, and then go on to mix the next batch.
A bonsai friend introduced me to the convenience of prescreened fir bark many years ago. I've been buying mine in 3 cu ft bags from Oak Hill Gardens, NW of Chicago (I pick it up usually 20 bags at a time), but before I discovered the fir bark, I had a number of sources I'd located that could provide a suitable size pine bark, which works just as well when screened to 1/8-3/8". You just have to keep your eyes open for something suitable. See my post dated 10/29 for suitable bark and my post dated 11/11 for what I use to screen the bark. The screens needn't be as elaborate ... it's just that I do use a lot of soil & the screens make it convenient for me.
Many use a fir bark product found in the pet supply depts of larger dept stores, called Repti-Bark. I understand it comes in 2 sizes, and the smaller size is the most appropriate.
I have tried some of the Turface in pots but am wondering if it has an order when wet.
The pot I used as a test with Turface (but not the correct mix ratio) was left in the rain and became fully saturated. When the temp dropped down into the 30's I brought the pot indoors.
Haste makes waste. I just haven't had time to screen my pine bark.
Turface is inert and has no odor of its own, but mixing it with organic ingredients that break down quickly can produce unpleasant smelling gasses, but the same can be said for any other inert soil ingredient as well. You're more likely to notice odors in any of your plantings if you use organic forms of fertilizers. Those would be things like various meals (blood, bone, hoof, horn, feather, cotton seed ...), fish emulsion, seaweed emulsion, and similar. An over-wet soil with as soggy layer at the bottom of the pot will find bacteria and fungi that thrive in anaerobic (airless) conditions working extra hard to produce the gasses associated with decay.
Make sure you screen your Turface through insect screen or a regular size mesh kitchen strainer before you use it for the very best results. The whole idea behind making the gritty mix is to produce a soil with particles large enough that it holds lots of air and no perched water. We depend on the fact that the bark and Turface are internally porous, holding water INSIDE the particles and not between them. This is the departure from soils made of smaller particles (peat, compost, coir, topsoil, sand ...) that makes the gritty mix and the 5:1:1 mix so easy to grow in and productive. When it comes to soil particles - size matters.
You are right! I did put a small amount of organic soil mix I had. No wonder it had a smell. I have some powdered fish emulsion that I can use only out doors since the smell is so strong. No wonder it was given to me.
I put my/your/our soil receipes on flash cards for convenience, but did not realize that Turface should be screened also. I would probably have to pulverize my Turface so it can be screened. Another "to do on Friday".
Turface already has a significant volume of fine particles that should be screened out for best results; so when you mention 'pulverizing' your Turface, it sends up warning flags. You can see what the finished gritty mix should look like if you scroll upthread to the second picture I posted on 10/29.
Exactly. You're shooting for a coarse mix that holds lots of air between the large particles, with most of the water being held within the porous particles. Water retention is closely linked to particle size. The reason most commercially produced and bagged soils are so difficult to grow in over the long term, is because the particles that make up the soil are so small that they hold water between the particles instead of air. All container growers will benefit significantly if they remain aware of how important ample volumes of air are to root function and plant health. Most of the problems container growers come to these forums with, seeking resolution, are the result of the heavy soils they are growing in. Even the disease and insect-related problems are most often the result of the plant's inability to produce the bio-compounds that form the plant's natural defenses against these pathogens; this, because of poor vitality and a sluggish metabolism resultant of impaired root function. Healthy roots are essential to healthy plants - no healthy roots = no healthy plants.
A little off-topic, but will this soil save begonias with root rot? All of my Begonias for some reason just decided to get root rot ( I'm assuming ), and I was wondering if I used this soil originally, if they would have it now?
In a technical sense, even the best soil won't cure the fungal infection that is root rot, but it will do an excellent job of ensuring root rot can't get a hold in two ways. First, by providing a well-aerated rhizosphere (root zone) that is hostile to the several common damping off fungi. Second, by ensuring cultural conditions favorable to root growth, health, and function, it offers the opportunity for plants to grow stronger; by that, I mean plants have the opportunity to glow at something much closer to their genetic potential compared to their counterparts in soggy soils. Since the bio-compounds that act in the plants' behalf as their defense against insects and disease are a by-product of the plants' metabolism, a more robust metabolism ensures stronger defenses.
We can't see what's going on in the rhizosphere, so we tend to disregard it, but roots are the heart of the plant, and they come first. The first thing to emerge from the seed is the root radical (tap root), followed later by the stem, & cotyledons. If you can't or don't keep the roots happy, there is no chance you can keep the plant happy.
The cultural condition most responsible for the fungal infections that kill roots is to much water and not enough air in your soils. These heavy soils are also largely responsible for the salt build-up that many of you are or will be dealing with this winter. I water freely, and I water on a schedule (gasp). I can honestly say that all I need to do to keep root rot at bay is to use just a little reason. I can't remember the last time I lost a plant to an issue relating to suspected root rot ... and I grow some plants rather sensitive to wet feet. and I grow them in very shallow containers (bonsai) that would normally seriously compound the problems associated with a heavier soil. The short answer is, it's very unlikely you'd be having a root issue with your plants if you were using a well-aerated soil and watering correctly.
It depends on the seeds I'm starting. If it was for veggies or bedding plants, I'd use the 5:1:1 mix made with pine bark fines:peat:perlite @ 5:1:1 respectively. Seedlings demand a medium with very good aeration if you're to minimize the probability of damping off diseases. for larger seeds, say for instance desert rose seeds, I'd sow them directly on top of the gritty mix and cover lightly with the fines I screened from the Turface. Alternately, if I was using the 5:1:1 mix, I would cover the seeds with about 1/8" of fine peat or sand.
The keys to a high rate of germination are: a favorable temperature (usually around 70*) and the right balance of air and water in the soil. The soil should NEVER be soggy - about as damp as a wrung out sponge is great. After germination, if you used bottom heat to bring the temperature of the soil up, remove bottom heat. Good light is important to strong seedlings, and air movement both strengthens the seedlings and adds an extra measure of protection against damping off diseases.
It's been slow here at Dave's the last few weeks, so in case I don't get the opportunity to wish everyone a Very Merry Christmas, I'll do it now. No matter what your religious views, I wish everyone happiness & peace in their hearts, not only during the Christmas and New Year holidays, but every day of the coming year and beyond, as well. Merry Christmas to all.
Al, what kind of soil do you use for tropical plants that like it a little wet? For example, I've read that elephant ears like soils that are "moist but well drained." What kind of a medium is both moist and well drained?
For plants that need repotting (as opposed to potting up) EVERY year to perform at their best (like Colocasia), I use a mix of 5 parts pine bark fines, one part of peat, and 1 part perlite. Keep in mind that even plants that do well in boggy conditions where they naturally occur, seldom tolerate the same boggy conditions in a container. A stellar example of that is the peace lily. It often grows in standing water at stream side, but quickly collapses in containers when soils are too wet - as will Colocasia.
Plants love lots of oxygen in the root zone; you can say the more the better, within reason; in fact, it's as important to have enough air in the root zone as it is to have enough water. Ideally, you would have a soil that holds a very favorable mixture of water and air. This is most efficiently accomplished by using larger particles that hold water inside the particles - like pine bark. To visualize, think of a jar of marbles as a soil magnified, but imagine the marbles as being porous. In your mind's eye, can you see all the wonderful air space between the particles to make roots happy? ... and the water IN the absorbent marbles being utilized as the plant goes about its business? Soils that are predominantly pine bark or other suitable particles employ the same principle.
The soil I use for Colocasia is in the middle. At 3, 6, and 9 you can see suitable pine bark fines from 3 different suppliers. The fir bark at the top comes prescreened & is what I use for the gritty mix.
Hi Tapla. My name is Joe. My wife and I recently aquired an umbrella plant from her grandma's funeral so I do not want to kill it. I use to grow a lot of house plants as a child so I kind of know what I'm doing but it's been some time. I have read how much to water it and how to prune it but my main concerns are light and soil. I have no available east or west windows available. However I do have a south window that lets through a lot of sun during the day. It has a mini blind that I open and the curtains are very thin and white, almost like there is not one there. Would this be suitable? Now on to the soil. I have noticed your posts about your soils and fertilizers. Is there a good way to make the soil or do you sell your soil? What type of fertilizer should I use? Also, the pot the plant came is kind of tight. It's a 1 gal and the plant is about 2' high and 2 1/2' wide. It about 3' high before I pruned it. The leaves are about half green and half white and it is very full. The roots are growing out of the holes at the bottom of the pot. One last thing. Do you know of some good, hardy low light indoor plants I could start growing in my home? I would love to get back into it and think that plants help make a house look much more homely and could also give me and my five boys something to do together. I appreciate any input. Thanks.
Scheffleras are very durable plants, so a good starting point or a good way to jump back into a collection of houseplants. Their care is pretty straight forward - lots of light, temperatures above 65*, water just before the plant is completely dry and use a soil that allows you to flush the soil when you water, a fertilizer with a 3:1:2 ratio (see the opening post), repot and root-prune (usually every 2 or 3 years) in late June or early July. You can prune them back VERY hard in the summer if they grow out of control. See one of mine upthread on my post dated Oct 26 of last year.
Obviously, I recommend a fast draining soil that is durable and can be counted on to provide aeration in the root zone for the full interval between repots. You can read more about soils here: http://davesgarden.com/community/forums/t/1073399/ Ask any questions you might have either here or at the other thread.
Your scheff and many other plants will do well in the south window. Most plants can adapt to the amount of light that comes through a south window, but the heat build-up on foliage can become an issue if air movement is minimal. The keys are to move the plant into full light gradually, over perhaps a 2 week period. Using a fan to interrupt the boundary layer (of air) surrounding leaves reduces heat build-up considerably, allowing you to give the plants more light, but watch foliage carefully. If you see signs of problems due to too much light of heat build-up, you'll need to correct. This is one of those areas that are going to vary from home to home & you sort of have to feel your way through or just play it safe.
I'll backtrack & answer your fertilizer question now. I really like Foliage-Pro 9-3-6. It supplies ALL the essential nutrients (most soluble fertilizers lack Ca, Mg, and other nutrients) in the ratio used by plants, and about 60% of its N is from nitrate sources. This makes for stronger stems and helps keep plants compact & bushy, something important for plants so often suffering from a lack of light. Alternately, use any other soluble 3:1:2 ratio fertilizer. Several manufacturers package 24-8-16 granular soluble fertilizers, and Miracle-Gro also has a 12-4-8 liquid. All the aforementioned fertilizers have a 3:1:2 NPK ratio (you can see RATIO is different than NPK %s).
You can pot up at any time with little concern except for the possibility of over-potting; that's IF you're using a heavy soil. Hopefully, after all this preaching, you won't be. ;-) Repotting, different from potting up, includes bare-rooting, root pruning, and a change of soil. That is required to prevent gradual decline, but it should be done in the month just prior to the plants most robust growth period.
I'll leave you to research the hundreds of plants available that you could try. Maybe a net search for "easy houseplants" or "easy to care for houseplants" would yield sites with lists; and maybe others that might be following along can relate the plants they're having success with.
Best luck. If you have additional questions or comments .
Talpa, thank you for sharing your vast knowledge with us all. Do you have a specific book you'd recommend for container gardening, landscaping, propagating, just about anything that has something with gardening.
I went to Dyna-Gro's website and found a store that carries the 9-3-6 ferterlizer about 35 miles from my home. Hope I can get there soon. In the meantime I am trying to finish up some of the ferterlizer I have(MG). I mix a weak solution and water my indoor plants plus those in the GH.
Am still working on gathering supplies to mix my own soil. I just have to wait for good weather to sift/separate my pine bark. I'll have to figure out a way to cut the larger pieces.
Oh, thanks, guys! I didn't realize that there were additional posts on the thread that hadn't received attention.
Thanks for the thanks, and you're both welcome. Hopefully what you learn will improve your skills and help you get more enjoyment from your growing experience.
P4P - Are you looking for books for yourself? a gift? what level of information do you want?
Most books on houseplants have conflicting information that varies by author; and the author takes a lot of liberties in assuming what type of soil you'll be growing in. For example, the advice to not fertilize in winter is offered to protect you from yourself. The author assumes you'll be using a peat-based soil that you'll have to water in small sips to avoid root rot. The practice of watering in sips ENSURES that salts will continue to build up in the soil. Since it's very likely your plant wouldn't survive the winter if you fertilized AND watered in sips, the advise is offered that you should avoid fertilizing altogether. If the author really wanted to do his readers a service, he would explain the soil/water/fertility relationship thoroughly, so you can see that with fast draining soils that you flush regularly, that fertilizing throughout the growth cycle is the best way to keep plants happy/healthy. When you consider that most books about houseplants are self-published by vanity presses, it's easy to see how there can be so much conflict in opinion and assumption on the author's part.
The two areas that offered the most advancement of my ability to keep containerized plants happy came in the areas of soil science & physiology. Understanding how soils work is a huge part of the equation - the biggest. Understanding how plants work and how to identify and reduce the effects of or eliminate limiting factors was also VERY important. Fortunately, the soil part is pretty easy. You can learn practically all you need to know about container soils here: http://davesgarden.com/community/forums/t/1073399/ After you let me know what kind of books you're looking for, I'll see if I can help you learn a little more about how plants work.
At another forum site, I wrote the following because someone had asked if Scott's Premium Soil was a 'good' choice. You may find it of interest.
Is Soil X a Good Soil?
I think any discussion on this topic must largely center around the word "GOOD", and we can broaden the term 'good' so it also includes 'quality' or 'suitable', as in 'a quality or suitable soil'.
How do we determine if soil A or soil B is a good soil? and before we do that, we'd better decide if we are going to look at it from the plant's perspective or from the grower's perspective, because often there is a considerable amount of conflict to be found in the overlap - so much so that one can often be mutually exclusive of the other.
We know that grower A isn't happy unless he is squeezing every bit of potential from his plants, and grower Z isn't happy unless he can water his plants before leaving on a 2-week jaunt and still have a weeks worth of not having to water when he returns. Everyone else is somewhere between A and Z; with B, D, F, H, J, L, N, P, R, T, V, X, and Y either classically ignorant (it just means they're not aware there is a difference) or they understand but don't care.
I said all that to illustrate the futility in trying to establish any sort of standard as to what makes a good soil from the grower's perspective; but lets change our focus from the pointless to the possible.
We're only interested in the comparative degrees of good and better here. It would be presumptive to label any soil "best". 'Best I've found' or 'best I've used' CAN be useful for comparative purposes, but let's tackle 'good', then move on to 'better', and finally see what we can do about qualifying these descriptors so they can apply to all growers.
I would like to think that everyone would prefer to use a soil that can be described as 'good' from the plant's perspective. How do we determine what a plant wants? Surprisingly, we can use %s established by truly scientific studies that are widely accepted in the greenhouse and nursery trades to determine if a soil is good or not good - from the plant's perspective. Rather than use confusing numbers that mean nothing to the hobby grower, I can suggest that our standard for a good soil should be, at a minimum, that you can water that soil properly. That means, that at any time during the growth cycle, you can water your plantings to beyond the point of saturation (so excess water is draining from the pot) without the fear of root rot or compromised root function or metabolism due to (take your pick) too much water or too little air in the root zone.
I think it's very reasonable to withhold the comparative basic descriptor, 'GOOD', from soils that can't be watered properly without compromising root function, or worse. I also think anyone wishing to make the case from the plant's perspective that a soil that can't be watered to beyond saturation w/o compromising root health can be called 'good', is fighting UP logic hill.
So I contend that 'good' soils are soils we can water correctly, that is we can flush the soil when we water, without concern for compromising root health/function/metabolism/. If you ask yourself, "Can I water correctly if I use this soil?" and the answer is 'NO' ... it's not a good soil ... for the reasons stated above.
Can you water correctly using most of the bagged soils readily available? 'NO' I don't think I need to point to a conclusion.
What about 'BETTER'? Can we determine what might make a better soil? Yes, we can. If we start with a soil that meets the minimum standard of 'good', and improve either the physical and/or chemical properties of that soil, or make it last longer, then we have 'better'. Even if we cannot agree on how low we wish to set the bar for what constitutes 'good', we should be able to agree that any soil that reduces excess water retention, increases aeration, ensures increased potential for optimal root health, and lasts longer than soils that only meet some one's individual (and arbitrary) standard of 'good', is a 'better' soil.
All houseplants, unless grown from seed, have the genetic potential to be beautiful specimens. It's easy to say, and easy to see the absolute truth in the idea that if you give a plant everything it wants it will flourish and grow; after all, plants are programmed to grow just that way. Our growing skills are defined by our ability to give plants what they want. The better we are at it, the better our plants will grow. But we all know it's not that easy. Lifetimes are spent in careful study trying to determine just exactly what it is that plants want, to make them grow best.
Since this is a soil discussion, let's see what the plant wants from its soil. The plant wants a soil that contains in available form all the essential nutrients, in the ratio in at which the plant uses them, at a concentration high enough to prevent deficiencies yet low enough to make it easy to take up water (and the nutrients dissolved in the water). First and foremost, the plant wants a container soil that is evenly damp, not wet. Giving a plant what it wants, to flourish and grow, doesn't include a soil that is half soggy for a week before aeration returns to the entire soil mass, even if you only water in small sips. Plants might do 'ok' in some soils, but to actually flourish, like they are genetically programmed to do, they would need to be unencumbered by wet, soggy soils.
We become better growers by improving our ability to reduce the effects of or eliminate limiting factors, by clearing out those things that stand in the way of the plant reaching its genetic potential. Even if we are able to make every other factor that influences plant growth absolutely perfect, it could not make up for a substandard soil. For a plant to grow to its potential, every factor has to be perfect, including the soil. We'll never manage it, but the good news is that as we get closer, our plants will get better and better. It's that one little factor that we willingly or unwittingly overlook that limits us in our ability and our plants in their potential.
A 2-bit plant in a $10 soil has a future full of potential, where a $10 plant in a 2-bit soil has only a future filled with limitations. ~ Al
John Deere Landscape has the Turface AllSport for $14.95 per 50# bag. -- I discovered that Granite Grit is widely used for chickens so I started calling the feed stores. One does not carry grit for chickens (??), another has "some kind of grit- looks kind of like crushed up rocks, not sure what it is" per the young unknowledgable girl that answered the phone but it is $8.00 per 5# bag, and the 3rd store I called does not have Granite Grit but has oyster shells for $8.00 per 50# bag...
Al, Do Oyster Shells have the same effect or do I need to keep looking??
I have not run across the pine bark yet. I only found it in the big box store in very small bags or in the mulch area. I did find that "soil conditioner" but it seemed to have too many fine particals of what looked like regular water retentive potting soil to me... I should have asked the guy at John Deere but guess I was so focused on Turface that it slipped my mind.
Avoid the oyster shells. They're almost all CaCO3, which makes for probable pH issues if used as a notable fraction of a soil, and they're high in salts. Try rural feed stores that cater to people who raise farm animals. You might be able to find Manna Pro chicken grit - maybe even at a bigger retail outlet. The other products to ask for are Gran-I-Grit crushed granite in grower size or #2 Cherrystone by New Ulm Quartzite Quarries.
See my post of 10/29/11 for an idea of what you're looking for in pine bark. If you're just making a small batch, you can use ReptiBark from a pet store until you find something suitable. Size IS important, so be sure you screen the ingredients.
I pay $5/50 lbs of cherrystone, and the last time I bought Gran-I-Grit it was about $7/50 lbs in grower size.
I ended up buying the reptibark at the pet shop. It's a nice size.
I had also compared the turface product's MSDS (material safety data sheet) with Oil Dri Floor Absorb (the stuff you use to soak up oil in garages) and it was the same exact components. Somewhere in one of the posts I mentioned it, but never did the freezer test to see if it would hold up. We sell the floor absorb where I work, I know it is way better than other floor absorbents so I wouldn't substitute anything else in that case.
Hi Al, first I want to say thank you very much for all the excellent posts and threads that you've provided.
I'm new to gardening and I probably read one of your posts about root pruning and then also looked for other threads here and youtube videos not finding much at all. Many say that you can cut off about 2/3 of the lower root system and I've seen one Bonsai person just saw off the bottom half or so. Now my understanding is that cutting the tap or primary root causes the plant to remain small or are there other factors? The reason that I ask is if I want to root prune a plant just to enhance growth but remain full size planted in the ground do I have to be careful not to cut back the primary root?
If you have a thread somewhere that I missed covering root pruning I would appreciate a link to it.
I tried root pruning a couple of inexpensive plants last week but did it simply to remove the old soil and any dead or poorly shaped roots. I did not cut them all back since I had not read about the roots closer in being younger and more vigorous. They are not doing very well with the leaves turning brown; I'm probably overwatering them. It is interesting that one plant in a gallon pot had many roots curving at about a 5" diameter probably from when it was in a smaller pot. These were both Blueberry plants and the roots were brownish, stiff and more wood like than the white roots seen on other plants. Is this normal for the type of plant or is it a sign of sick roots?
Also, it seemed as if some of the fine roots were even darker and just fell off - guessing here, dead from overwatering?
I'll try to take your post point by point and offer comments. First though, thank you for the kind words. For me, being able to believe I might be having a positive influence on the growing experience of others is what justifies the effort of posting, so your comments are appreciated.
How much of the root system you CAN cut off depends on several factors, among them are the type of plant (how genetically vigorous it is), timing (where the plant is in its growth cycle), the state of the plant's health/vitality level, and the growers ability to provide appropriate after care. The pictures below show a before/after sequence of a boxwood I pruned this spring. You can see I easily removed 90% of the roots from a tree that isn't very vigorous, genetically, and it recovered quickly w/o problems. Oops - I'm at work & don't have access to my photo files, so I'll have to post the pictures later.
Root pruning is more than just sawing off the bottom of the roots. A full repot involves removing all or a large fraction of the soil and selectively removing roots, concentrating on the problem roots first, and then the largest roots NOT attached to the stem. Severing the taproot doesn't keep a tree smaller or limit growth in containers. The smaller size of containerized plants is more rightly attributed to cultural conditions, primarily root congestion and less favorable soil temps compared to plants planted out, but watering habits, poor soil aeration, and nutritional issues all play their part as well. There are some fine points that make the following statement not quite 100% true, but for the most part, root pruning doesn't enhance growth unless it's done to relieve root congestion or correct problems associated with encircling or girdling roots, and then it shouldn't be said that it 'enhances growth'. It actually only allows the plant to return to a state closer to normal growth as defined by its genetic potential.
I don't think I have a thread here (Dave's) that addresses root pruning, but the information here http://forums2.gardenweb.com/forums/load/contain/msg0417334631829.html goes into considerable depth about maintaining trees in containers for the long term. Almost all of the information is applicable to houseplants with root systems that lend themselves to root pruning.
The growth habit of roots varies by plant. Some plants have very fleshy or tuberous roots, some have very fine and thread-like roots, and others have roots that lignify (get woody) quickly. Root health is very closely related to soil choice and watering habits, and deserves far more attention than it gets. Blueberries and other temperate plants in your zone are usually best replanted in the spring, or sometimes in late fall. Houseplants are best repotted or root pruned in the month prior to their most robust growth period - usually around Father's Day for most of them.
I am new to gardening and would like to start a small assortment of flowers in my house. I am finding it very hard to start from seed. I have planted Carnations, Coreopsis and Portulaca so far. The portulaca has sprouted ok but seems to not grow any true leaves. The caranations have also sprouted but wilted soon after. Still waiting on the coreopsis, its only been like a week. The soil I am using is Shultz Feed Starter Plus. And for the time being a have them under a reflected 125 W CFL. Input would be much appreciated even .
Hi, Chris - All of these plants will prefer a life outdoors and will probably rebel at indoor conditions. Try starting them after the vernal equinox, during long days and increasing day length - use bottom heat and a fan. Ideally soil temps would be about 70*, and air temperatures about 10* cooler. As soon as the seeds germinate, eliminate bottom heat. Keep the soil barely damp - about as damp as a well wrung out sponge.
Thanks for the input. I'm sort of just playing with it and looking to see what might do well. I here that carnations can do very well indoors and I'm waiting for the last piece of a grow light I'm building. I have a pic of the portulaca, its alive but doesn't seem to be making any progress. I wont really mind if they don't flower for a long time but if I can keep them nice and alive until spring that would be cool. But I might just be doing something crazy.
The moss rose is an annual that is genetically programmed to die as winter approaches, so I don't think you'll have much success with it until at least after the winter solstice, and you can expect much better results after the vernal equinox, unless you're willing to carefully manipulate the day length by completely controlling the duration of photoexposure they receive. The same would be true of the Dianthus and tickseed, even as perennials, they are programmed to react to decreasing day length by preparing for dormancy, so they're not going to want to grow now.
Try antirrhinum (first two pictures). I don't know if it will come for you from seed at this time of year, but I've had success with blooming them indoors over winter from established plants. Dwarf hibiscus (last picture - middle) is another plant that blooms all winter for me indoors. I've had some decent success with Impatiens repens, as well, if you can find it.
You're probably going to have better luck looking for houseplants with colorful foliage or known to be reliable winter bloomers to help keep the cabin fever at bay.
Some products intended for use as an oil absorbent can be used in soils and some can't. They need to be of appropriate size and structurally stable. Some of the products are calcined (baked at high temperatures) clay and some are calcined DE (diatomaceous earth) - either will work if it's fired at temperatures high enough to ensure its stability in soils. You don't want to include it in a soil, only to find it turns to mud when it gets wet, like some low-fired products do. A good way to test it for stability is to freeze it solid in a cup of water overnight. If it's stable when it thaws, it's fine for use (if it's the right size). Ideally, the particles would be in a size range from about half the size of a BB to about twice the size of a BB.
ficus, I asked about the Oil Dri. I never did test it. We distribute it where I work, I will go out tomorrow and find a broken bag & put some in the freezer.
I know it is a clay product, and the manufacturer advertised it as "thrice baked". We had carried some less expensive product at one time & had nothing but complaints about it's breaking down & becoming mud, so hopefully the Oil Dri holds up.
Al, how much would I put in a cup of water, do you think?
No need for more than a tablespoon, but as much as you wish. If the particles hold together after freezing, it should be ok to use. Again though, make sure the particle size is appropriate, and if you're using it to make the gritty mix, you screen the fines out.
More about the gritty mix if you follow the link provided. The important part of putting soils to work FOR you instead of against you is understanding how they work and what affects how much water they hold. That's all explained Here:
Hi Al, I am planting several blueberry plants outside and we've dug about 16" deep holes since I read that they need to be well drained and I wanted to provide a good quality mix. The largest plant was in a fairly large 3 gal container and I removed it and all the soil from the roots finding that the roots did not go much more than 3" into the mix. Also, the taproot and most of the large roots were spiralled as if it was in a 6" pot at some time.
Is there anything I should do about these large roots?
From what I understand the large clusters of smaller roots have much more surface area and therefore ability to take up nutrients than the large roots. I was wondering if the taproot does much more than provide a footing for the plant so that it does not fall over?
Lastly, does the mix down 12 or more inches do anything more than provide drainage? Do nutrients or soil PH matter that far away from the roots?
I am planting several blueberry plants outside and we've dug about 16" deep holes since I read that they need to be well drained and I wanted to provide a good quality mix. The mix isn't what's going to determine how good/poor drainage is, it's the percolation rate of the surrounding soil that does that. If you dug your hole in clay, you probably created the bathtub effect, but if you dug the holes in loam, you should be ok in where drainage is concerned. It's also generally considered poor practice to amend the soil in planting holes when the native soil is anything but sandy. The largest plant was in a fairly large 3 gal container and I removed it and all the soil from the roots finding that the roots did not go much more than 3" into the mix. Also, the taproot and most of the large roots were spiralled as if it was in a 6" pot at some time. Is there anything I should do about these large roots? Well, it sounds like your plant might have been recently potted up after having been left to languish too long in the same container. Plants should be potted up BEFORE the roots get congested to the point the root/soil mass can be lifted from the plant intact. If the roots are left to grow beyond this point, there is a near certainty that problems caused by the shape of the roots will permanently affect growth and vitality permanently. I don't know how comfortable you are with doing root work, but if they were my plants, I'd definitely get into the roots and correct any potential problems before giving the plants a permanent home.
From what I understand the large clusters of smaller roots have much more surface area and therefore ability to take up nutrients than the large roots. It has more to do with the fact that the young, often almost microscopic feeder roots, are most efficient at absorbing water and the nutrients dissolved in water. As the plant ages, some of the fine roots die and the plant goes through a regeneration process when conditions improve. Other roots remain viable and grow in diameter as the root extends, They also undergo physiological changes that make it more difficult for the root to take up nutrients, leaving the roots primary functions conduction and anchorage. I was wondering if the taproot does much more than provide a footing for the plant so that it does not fall over? No - it doesn't. Technically, a tap root is a primary root that emerged as the seed radical, so plants produced from cuttings or tissue culture don't have taproots. Instead, they usually have multiple secondary roots that grow downward and serve the same function as a taproot.
Lastly, does the mix down 12 or more inches do anything more than provide drainage? As noted above, in-ground drainage will be determined primarily by the surrounding soil, not what's in your planting hole. Do nutrients or soil PH matter that far away from the roots? For the most part, they have no influence on the plant unless they provide a home for the roots, but if there is something about the soil that has an impact on the chemistry of the soil solution, it could have an impact. For instance, you might mulch with or fill a planting hole with mushroom compost, which is often high in soluble salts. Even if roots aren't actively growing in the compost, the influence it has on soil chemistry can impact the organism.
This is kind of off topic for this thread. I'm happy to answer any questions I can, but maybe you could start a thread in a more appropriate forum & D-mail me a link to it?
So is the 5.1.1 mix or the gritty mix better for peace lillies? These are my favorite plants but I've lost about 5 of them since 2003, it was because of root rot. I have two at the moment and one is looking kinda poor. I've had it over a year now and have repotted twice. I also have root pruned it. I live in a rural area and we have a feed and seed store across town so I think I'd be able to get most of the ingredients. Thanks for the help Al!
Because they really should be repotted every year, I use the 5:1:1 mix for peace lilies, and it works very well. I never have trouble with burned leaf tips and margins, and they always bloom well in the summer for me - sporadically throughout the rest of the year, but that varies by cultivar.
I'm sure Al, who is very good about answering questions (unlike me), will tell you that in order to maintain maximum root virility, almost all plants should be repotted annually. However, just to give another perspective on the situation, as an interior landscaper I have taken care of hundreds of peace lilies, many different varieties, many different light conditions, kept them looking spectacular for years, and never repotted one. Also these plants were in commercial soilless potting medium, not water retentive as "potting soil" from the store, but not nearly as porous as Al's mixes, either.
I think the real crux of the matter revolves around root health/soil moisture, and the amazement derives from the abilities of plants to adapt to their environments. Yes, you can maintain healthy roots in an extremely porous mix watered every few days. Yes, you can also maintain healthy roots in a much less porous mix by paying close attention to the moisture level near the bottom of the pot, and not watering until the soil has reached a slightly damp condition, in which a small amount of soil pinched between your fingers will barely stick together when you let go of the pinch. Keeping the soil too wet is the main reason people have trouble with peace lilies.
Regarding repotting, yes you will probably have very healthy plants if you repot according to Al's instruction. However, in interior landscaping, annual repotting is an unattainable luxury, but still the plants can be beautiful, in spite of old roots, compacted soil, etc. How is this possible? I believe it is because interior landscapers use plant species that have an extremely wide rang of adaptability. Peace lily - spath - is an especially strong example of that ability. As long as the soil is not kept too wet, or too dry, for too long, and not fertilized too much (this keeps the soluble salt level from escalating), the plants stay beautiful.
So you have two approaches to growing potted plants. One (porous medium) requires more work (mixing soil, repotting plants when you buy them, watering every 2 -3 days, etc), the other requires more analysis in the beginning (determining soil moisture before watering, possibly keeping some sort of records,) but after that, watering once a week, or every other week, is the main effort. Some people prefer the first approach, some the second. If anyone is interested, I could try to go into more detail about the "professional" approach.
SS - Sorry - I missed your post. Root congestion slows growth and reduces vitality in plants. About the time the root/soil mass can be lifted from the pot intact, growth and vitality are already being reduced. As root congestion increases, growth and vitality decreases. Vitality is a measure of how well a plant deals with the cultural hand it is dealt, so anything stressful is going to impact growth and vitality. Stress, is an indication the plant is operating at the limits of what it is genetically programmed to tolerate.
I think the fact that at LEAST 90% of the PL problems people come here looking for resolution to are related to over-watering, is ample evidence that soils that support significant volumes of perched water are extremely problematic for a very high % of growers, especially beginners. Maintaining maximum root health is ONLY possible in soils that hold little to no perched water. I can make that statement because we know that the function of roots within the soil mass occupied by perched water are always negatively affected. It simply is not possible to achieve the same potential in a soggy soil as it is in a well-aerated soil.
In a soil that requires water every week or two, there will be a saturated layer of soil at the bottom of the pot, due to the soil's small particle size. This soggy soil negatively impacts growth and vitality until ALL the water that exists between soil particles is used up. In a highly aerated soil, all or nearly all the soil is contained within the soil particles, leaving the space between the particles full of air. This is the ideal scenario from the perspective of plant health.
CAN you grow acceptably healthy plants in soils that are able to go 1-3 weeks between waterings? That's for the grower to decide on an individual basis - how much growth/vitality he/she is willing to sacrifice, because it's not possible to use these soils w/o paying for the convenience of these long intervals with reduced growth and vitality. Most of the growers needing help with their soils are already allowing a week or two or three between waterings, so what added strategic benefit can there be, other than letting their plants dry down even more between waterings? Then, how do you justify the soggy soil at that the bottom of the pot that create those conveniently long intervals? You can't.
I don't think we have two different ways of growing plants, or a 'right' way vs a 'wrong' way. What we know is that the potential for healthy plants increases as soil aeration increases (within reasonable limits, of course), and it decreases as aeration decreases. Period. This also means that the potential for healthy plants increases as required watering intervals decrease. We should be looking at ways to build soils that require MORE frequent watering instead of trying to learn how to cope with soils that offer these 1-3 week watering intervals. The regular stream of growers flocking to the forums for relief from their heavy, water-retentive soils, along with the thousands of testimonies of growers who have changed from water-retentive soils to soils that are highly aerated, is undeniable evidence of which offers greater potential.
I have posted threads with plenty of tips to help growers DEAL with the negative effects of perched water and soils that allow these extended intervals between waterings. The tips suggest a number of ways of removing some or nearly all of that excess water, and these are very helpful insofar as increasing the plants potential, but by virtue of the fact that these soils are soggy BECAUSE they lack aeration and the particle size is very small, even after excess water is removed they are not capable of providing as healthy an environment as soils that need no extraordinary effort to help drain excess water - they are not as well-aerated.
Hi Al, I totally agree with you about the use of gritty mixes and I am gradually changing my own plants at home over to this way of growing.
However, as a newcomer to interior plantscaping I am asked to look after my clients houseplants and I can only water their plants once a week or even once a fortnight and the clients will not water the plants themselves. Like other indoor landscapers I have a quandary...if I use a gritty mix and only water once a week the plant may dry out and if I increase the water-retention of the soil I face the danger of perched water etc.
I guess that though the gritty mix is the ideal that sometimes we have to make compromises if the plants can not for genuine reasons be watered every two or three days.
I would appreciate advice on this, I am still trying to work it out for myself
... and I completely agree with your observation, Mike. Because of time constraints and monetary considerations, interiorscapers are, more often than not, forced to make choices that allow them the extended intervals between visits they need to ensure a profit and fit everyone into the cycle. That's not wrong, it's just a fact of life.
Readers should understand that we're examining plant rearing from two different perspectives. You need to make a profit and need the convenience afforded by visits a fortnight apart (or some set interval). I'm primarily interested in showing growers who DON'T need to make a profit and CAN afford the time it takes to water every few days, how to get the most out of their plants. So, one view is with profit and convenience as the pivotal point, the other view is from the plant's perspective - what is best for the plant, which is how I tend to look at growing. FROM that perspective, we can get a clearer look at what the cost of convenience and compromise is - and there is always a cost.
That cost might not always be readily apparent because it often comes in the form of lost potential, which, where growth or yields are concerned is never recoverable. Some growers are passively compromising via their soil choices because they don't realize they have options. Others realize there are options, but are forced to compromise by time constraints; and still others are forced to compromise by how they order their priorities. It may be that a hobby grower works all day and feels it's more important to squeeze in an extra evening walk twice a week than it is to water plants. Again, that's not wrong, it just is what it is. Even if a grower would rather watch his favorite TV show instead of watering a little more frequently - who's to say there is anything WRONG with that? There shouldn't be a stigma associated with making compromises, but we do need to recognize them for what they are. I can help growers understand how to optimize root conditions and ensure your plant at least has the opportunity to grow as near to its genetic potential as possible (within the effects of other potentially limiting factors), but that doesn't mean everyone can, or will even want to, make the effort.
I think that because you understand the concept, it will always have the potential to be helpful; but like you said, you'll have to work out whether or not you can apply it or to what degree it can be applied in various situations.
Let me know if there's any way I can help you. Happy Thanksgiving!!
I am maybe about halfway through this thread, so you may have answered this question before. I'm a slow reader, but I do intend to finish reading, as I'm getting a great education on proper houseplant care. I'm still new at it, but have been growing garden perennials for quite a few years now. I'm learning A LOT in through this thread. Excellent info.
My question to you will begin with a statement. I grow a lot of garden perennials (mostly daylilies) in containers to sell (extra money to pay for my gardening hobby [addiction]). I use either just regular garden soil or a mix of MG and composted cow manure (the latter I just started doing this year, and I repotted and root pruned many of my older pots of daylilies, which have responded well). Both types of soil/soil mixes have worked out well for me, but do you think I would do better with the gritty mix you use for the house plants, and should I use it in containers of annuals for outdoors as well? Seems I need more water retentive soil on the outdoor containers, unless I want to be watering every day, which is what I already do in really hot weather. I wouldn't want to have to water more than once a day on most of my containers, although I've read that Brugmansias really need twice a day watering during hot weather and twice a week fertilizing throughout their growing/blooming season (thankfully I only have 2, which need repotting next year, as they're really root bound and in dire need of fresh potting soil).
I forgot to add here that a lot of my "houseplants" move outside during the summer. I did read just a bit further and found you used your 5:1:1 bark based mixture for your outdoor mixed containers. Should I go with this mixture for my indoor/outdoor plants, rather than the 1:1:1 mix, which requires a lot more watering? And should I use that same mixture for the outdoor potted perennials that I'm selling?
Hi, Karen. In most cases, I can help growers with suggestions/facts/concepts, based on what I know of the plant sciences and validated by my own personal experience, that will allow them to consistently produce healthy plants. Some growers are already happy with how their plants perform. I'm not interested in trying to talk those growers into making any changes unless they want to, or suggest they SHOULD be doing something another way. If what they are doing is good enough for them, it's good enough for me, too. You might find me debating what course offers the most potential, or how a grower might best direct efforts to achieve a particular end, but I can't tell you what's right for YOU. We know that soils with superior aeration and drainage offer better opportunity for plants to grow as close to their genetic potential as possible, but it's the grower that needs to consider what strategies to implement and which to pass on.
Often, what works or works well, can hinge on a subtlety. For instance, if you use a mixture of MG and composted manure in a conventional way, ie in a pot with a drain hole on a deck railing or over a collection saucer, you might have more water retention than you want or need; but, the same soil/container combination setting on top of the soil in a garden or bed might be an excellent combination because it employs the earth as a giant wick to help drain excess water from the pot. So, if you understand how/why water moves or is retained in soils, you can put that concept to work for yourself instead of having to fight it.
Growing plants to sell might find you looking at that aspect of husbandry with a different perspective than when growing plants over the long term in containers for your own enjoyment. Keeping a plant eternally healthy and happy is different than simply ensuring a plant of saleable size and acceptable health at the point of sale.
I use the gritty mix for long term plantings simply because of its greater potential. I don't mind the fact it requires a little more watering than the 5:1:1 mix, which requires more watering than almost all commercially prepared mixes from a bag. I adjusted my thinking many years ago on this whole watering thing. ;-) The fast-draining soils I use don't require watering too frequently - the more water-retentive soils require watering too INfrequently. If you have an oven with only 2 settings, one is 300* and the other 600*, and the 600* setting won't cook food through w/o burning it on the outside, do you draw the conclusion that 300* is too slow, or 600* is too fast? ;-) Soils are the same way. We might be better off if we judge all soils against those that offer the best potential, but even then we can be certain that our choices will be tempered by how we order our priorities. It does no good to use a high quality soil that requires watering every 3-4 days if you can only set aside the time to water weekly ...
You asked if I was a MG. I took MG training a long time ago, and was a very active member of the local MG's club, along with several other area garden-related clubs/societies, but I sort of lost interest in the MG's club after a few years. Ours just had too much politicking and too many internal control issues going on for my taste. My current interaction with the area MG clubs is limited to the presentations/talks/demonstrations I'm often invited to give and so much enjoy.
That answers a lot, Al. Most of the potted perennials I have for sale are sitting on the ground. I have smaller pots on wooden tables, and some on a plastic table. My containers of annuals are usually sitting on the ground our up on chairs in the gardens, and some are hanging.
I thought you might have had MG training, as you're so knowledgeable. Thanks for taking the time to share your knowledge with those of us who are thirsting for out. I like doing the same. Whenever someone stops by to buy plants, I take them on a tour of the gardens if they show an interest.
Coir has its inherent problems. It's high pH precludes the use of dolomite as a Ca/Mg source, and it's extremely high K content should be taken into account so adjustments can be made in your fertilizer supplementation program - not the easiest thing to do for the hobbyist when most fertilizers already have adequate amounts of K or more than needed in relationship to N - like all 1:1:1 ratio fertilizers (such as 20-20-20, 14-14-14, etc).
Coir's water retention curve is very close to the same as peat - on a (particle) size for size basis, and it breaks down a little faster than peat. It is also very often very high in soluble salts due to salt water processing. Most commercial enterprises that DO use a fraction of coir in their soils, limit its presence to less than 10% of the o/a volume because of its inherent issues.
Forgive me for disagreeing, but "50% soil+25% vermicompost+25% coco-peat" will yield an exceptionally water-retentive soil - water-retentive in the extreme, in fact. All the particles would be extremely fine, which ensures a very high perched water table (soggy layer at the bottom of the soil after watering well) and problems dealing with it for a very high % of growers. There are much better choices based on materials with a larger particle size.
If you're happy with the results you get with your choice of soils, that's all that is important. To others, I would note that the list of issues associated with that particular blend of ingredients has nothing to do with geography. Excessive water retention is just that - excessive. It's as excessive in India as it is in Kazakstan or here in Michigan, USA. You may be willing to suffer some of the limiting effects of a soggy soil for the convenience of not having to water so often, but a soggy soil limits plants in India just as it does in Michigan ... and that's just one of the potential issues - there were several others listed that go beyond the subject of water retention that are valid considerations.
Much depends on perspective. Where you suggest that adding coir to soils where it's hot is preferable - I say that a plant-healthy soil and watering more frequently would be my preferred method of dealing with the heat. Especially since highly aerated soils are capable of keeping roots as much as 15* cooler than their water-retentive counterparts; this, because of the increased evaporative cooling that comes with a well-aerated soil's superior gas exchange.
For me this mix holds good in containers because the water evaporates quite quickly. And again for huge containers or lawns I completely agree with you Tapla, the mix would be soggy.Even in smaller containers depending upon weather I am watering, generally a glass of water everyday. So it all depends.
Okay, Al, I have finally finished reading your thread, and I think I'm understanding it quite well. From what I understand, all my house plants should be repotted around Father's Day, correct? I should just leave them the way they are until then? Not that my plants look bad, really. Most of them look really nice. The only one I'm having trouble with is a recent purchase of about 2 months ago, and Alocasia called 'Stringray'. Nice looking plant, but it's not doing well. Seems the soil is too moist, and it's not drying out. I watered my plants last week, but did not water that one. It is still wet. I do have to pot that on up, as well as another Alocasia and a bird's nest fern. I have 2 of the latter, and I just love them.
B - lawns aren't usually a problem when using fine soils because they employ the earth as a giant wick, so soils that work perfectly well in the landscape are almost always very poor in a container. Excess water-retention and lack of aeration are the main reasons why, and plants where you live need air in the root zone to function well, as bad as well as plants where I live. Also, large (deeper)containers are much easier to grow in than shallower containers. See the sketch below.
If container 'A' is 12" deep and the PWT after a proper watering is 4" deep, as indicated by the shaded area, 33% of the soil would not drain, leaving 2/3 of the soil w/o perched water. If the container was only 4" deep, the entire soil mass would be saturated after a proper watering, leaving the entire container a saturated mess. Because this saturation impairs root function, ie the plants ability to absorb and move water efficiently, the plant will use the water much more slowly than it would in larger pots. Also, due to the habit of watering in sips (by the glassful), you ensure that ALL the dissolved solids in your irrigation water that aren't used by the plant will remain in the soil, ADDING to the TDS/EC (level of dissolved solids in the soil solution) and making it increasingly difficult for the plant to take up water and the nutrients dissolved in that water.
"It all depends" is a vague term, but in this case we can depend on the fact that soils with a fraction of small particles as large as you're suggesting (100%) are going to present physical barriers to good root and therefore good plant health. From the plant's perspective, it would be MUCH better to use a well-aerated soil and water more frequently than to depend on stacking more water than necessary into the PWT to act as a reserve, because that reserve can ONLY be limiting. From the grower's perspective, it might seem like a good idea because it relieves you from the need to water as frequently as in a healthier soil, but that doesn't change the negative impact on the plant. That the water in a soil evaporates quickly just means that the plant is subjected to limiting conditions for a shorter duration - it doesn't eliminate the negatives associated with a water-logged soil.
I have no stake in how you tend your plants, but I would like others to realize that soils with collectively predominant fractions of fine ingredients are going to be problematic - no matter where you live ... and that doesn't even address the chemical issues I mentioned that are associated with a large fraction of coir in soils.
Hi, Karen - There are a few plants commonly grown as houseplants (citrus comes to mind - azalea, too) that might better be repotted earlier in the spring, but the largest fraction by far (prolly 95-98%) would best be repotted in the month prior to their most active growth period. That period between Father's Day and the 4th of July usually finds plants that have some stored energy due to the longer days, and temperatures that allow us to have had our plants outdoors. A lesson taken from bonsai is that trees that are allowed to grow unencumbered by pruning and are bursting with energy will tolerate a lit of indignities their weaker counter-parts won't. Basically what you are doing is tapping into the plant's natural growth cycle and its ebb/flow of energy, and getting the plant's natural rhythms to work FOR you, instead of against you. Lol - that's not some crazzy 'Zen' thing I made up, it's one of the basic tenets of bonsai culture, one that is readily and easily applied to all plants.
There are two gas stations on a road that runs from the bottom of the mountain to the top. If you run out of gas half way up the hill, even 5/8 or 3/4 of the way, and your only option is to push your vehicle to the fueling station, are you going to push it uphill or downhill? Repotting is sort of the same. It might not kill your plants, and you might not even SEE the lost potential, because lost potential is pretty much an intangible, but it is there. When I repot (different than potting up) in the summer, I see evidence of new growth, usually in a week or two after the effort. If I do an emergency repot in the winter, I can usually expect the period between the work and evidence of new growth to be measured in months, instead of weeks. During that recovery period and in that weakened state, the plant is unnecessarily more prone to attack from insects and disease. It just makes good sense to learn to work WITH the plant instead of against it. ;-)
Tapla - You are very scientific, the wick explanation is fantastic and made it clear that I am just lazy watering the plants ! and I also got the whole concept wrong.
I was thinking in only one dimension i.e. Large container will need more water and will retain them for a longer time, while small containers need less water and it will be used up/evaporated in a day(in our tropics atleast) so that's why I added coco-peat (ignoring this Root saturation problem as in figure B). Must be the reason why my dad scolds me that I am giving too much water to plants.
By the way please tell me if over-watering makes the leaves more yellow or green or to put it simply how do I ever know if I've over-watered or under-watered a given plant, are there any visible clues?
I am also planning to dilute either some dried cowdung (an let it sit for a day) or Epsom salt in water and apply as a foliar feed (I've come across this new term on internet) is it a good idea?
I have with me right now are Red soil,Coco-peat,Vermicompost,Super phosphate,Dried cow-dung,about 10 gms of Epsom salt and sand (to be gathered from a construction site), considering the above list can you suggest me a mix for Rose plant.
Al, I sure do appreciate all the great information. I now have to gather up all the soil ingredients for this coming summer. I for sure need to repot a couple of Christmas cacti ASAP. I repotted them about a month or so ago, before reading your thread, and I used cactus potting soil, thinking that would be a good thing for them. Well, the soil is holding way too much water for them. I have not watered them in 3 weeks, as the soil is still damp. I'm worried they're going to suffer if I don't get them in a coarser mix soon.
will explain it in greater detail, if you have an interest. You're being much too hard on yourself by calling yourself lazy, which I'm sure is not the case. Even if you fully understood the concept and chose an extended interval between waterings at the expense of plant vitality, no one should suggest you're lazy. We all order our priorities differently, and none of us knows what's best for you. We can usually speak with a fair degree of certainty about what might be best for the plant, but not the grower.
The symptoms of over-watering are almost exactly the same as under-watering. This is because over-watering also makes it more difficult for the plant to move water to its distal parts, so plants can actually be dying of thirst in a sea of plenty when they are over-watered. Over-watering also makes it more difficult for the plant to take up certain elements under water-logged conditions, so nutritional deficiencies can also be a problem in water-logged soils, even when the supply of nutrients is entirely adequate.
Test your soil by pushing a wood dowel or bamboo skewer deep into your pots. If they come out wet, cool on your inner wrist, or dirty looking, withhold water until the skewer comes out clean - then water THOROUGHLY. If you CAN'T water thoroughly w/o risking root issues, maybe a closer look at your soil's composition is in order.
Foliar feeding is used primarily in agriculture when a crop is growing so fast it cannot get all the nutrition it needs via the primary pathway. Nutrient applications are usually limited to one or two nutrients shown to be deficient by tissue sampling. If you DO see any notable improvement after foliar feeding, it's probably a good indicator there is something wrong with your primary supplementation program. Also, some plants are much better able to absorb nutrients applied to foliage than others - so it's possible in many cases that your efforts might go for naught. You can only gain by foliar feeding if the nutrients you are supplying are indeed deficient in the plant. If there is no deficiency of what you are supplying, there is NO potential for gain - it can only limit.
I don't know what all you have available to you for making soils, but I would suggest that you try something based on larger particles than the possibilities on your list. The two soils I use are shown below.
Tapla:- Well well well your soils (2 pics above) look like Kellogs Corn!! I have never seen this sort of soil in my area, not even in the pots of any of our neighbours. By the way in the first pic I could see nice Sunflower seeds if I am right and in the second pic I am not sure why you put a coin (probably seed for a money plant LOL!?)
Now I am about to follow your third link (Water Movement and retention)
Al, I did not get that before. Thanks for pointing that out. The cactus is not too big, maybe an 8" pot, and one in a 6" pot as well. I will try tipping those, as well as my 2 small Alocasias, which I think are in 6" pots, and are also too wet. I gave them a really good watering a few weeks ago, and they have remained wet. One is not doing so good.
Tapla: I've learned that raw wood products like Sawdust would not let plants to thrive absorbing all the Nitrogen (that plant roots should feed on) to decompose quickly. Wouldn't such a thing happen when you add fir bark etc,. (as u suggested in your mixes?)
No - there is some N immobilization in all container media, unless it's a completely inorganic mix. Fir bark breaks down very slowly in containers, as does pine bark. That fact, plus their larger size compared to ingredients like peat, compost, coir, sand, topsoil ... is what makes them so attractive. Sawdust is very fine (texture), and comes from sapwood/heartwood. As such, it lacks the suberin contained in conifer bark. Suberin is a lipid that makes it very difficult for soil organisms to cleave the bark's hydrocarbon chains, which is what gives it its structural stability and makes N immobilization a minor issue. Sawdust has several issues - it's size, N immobilization, heat generated during the composting process which can be considerable, a high pH spike that occurs during composting, and perhaps others that don't immediately come to mind, but what's mentioned should be enough to keep you from considering it as anything but a minute fraction of a soil.
Karen is correct - because container culture is much closer to hydroponics than growing in the earth (maybe 7 or 8 on a scale of 1-10), the N issue can easily be addressed in freely draining soils with frequent applications of fertilizers at low doses. I always reach for fertilizers with an NPK RATIO (different than NPK %s) of 3:1:2. Examples commonly used are 24-8-16, 12-4-8, and what I use - Foliage-Pro 9-3-6.
Sorry - decomposition would be too rapid. You want to take steps that relieve you of the effects of perched water, yet still offer good water retention. I think you would be better served if you moved toward the inorganic side ... i.e., if you have complete fertilizer available with all the essential major and minor nutrients. See the second picture I posted on 12/3. Do you have crushed lava available, or something similar to our Haydite? How about doing a search for calcined clay or calcined DE?
The article I linked you to over at the container forum will always serve you well, as long as you understand the concept and recognize that PWTs are indeed a problem. Here is something I wrote about how to deal with excess water retention in your soils. It should also be helpful:
Dealing with Water-Retentive Soils
A good friend recently asked me if putting a brick in the bottom of a container interferes with drainage? After reading the question, it occurred to me that there are aspects to the question that I’ve discussed very little here @ Dave's. It also occurred to me that I could use her question to help those who grow in heavy (water-retentive) soils. I’m going to define those soils, but this isn’t about disparaging soil types - it’s about helping you try to squeeze the most plant vitality (and the water) out of them. Heavy soils are based on fine ingredients. If the soil contains more than 30-40% of any combination of peat, coir, compost, or other fine ingredients like builders sand or topsoil, it will retain appreciable amounts of perched water and remain soggy after it’s saturated, and this is about dealing with soggy soils.
Perched water is water that remains in the soil after the soil stops draining. If you wet a sponge & hold it by a corner until it stops draining, the water that is forced out of the sponge when you squeeze it is perched water. From the plant’s perspective, perched water is unhealthy because it occupies air spaces that are needed for normal root function and metabolism. The gasses produced under anoxic (airless) conditions (CO2, sulfurous compounds, methane) are also an issue. The main issue though, is that roots deprived of sufficient oxygen begin to die within hours. You don’t actually see this, but the finest, most important roots die first. The plant then has to spend stored energy or current photosynthetic (food production) to regenerate lost roots - an expensive energy outlay that would otherwise have been spent on blooms, fruit, branch extension, increasing biomass, systems maintenance ….. Perhaps the plant would have stored the energy for a winter’s rest and the spring flush of growth instead of expending it on root regeneration.
You can see that perched water, from the plant’s perspective, is not a good thing. From our own perspective, we think it’s rather convenient when we only need to water our plantings every 4-5 days, but because we can’t see it, there is a sacrifice in potential growth/vitality for our convenience - like driving on low tires reduces fuel economy. How we choose to resolve this issue is of no concern to me - we all arrange our priorities & few of us are willing to water plants every hour to squeeze the last wee bit of vitality from them. Growing is about compromise in more cases than not. There is no judgment passed here on soil choice.
If you don’t agree that perched water is generally a bad thing in containers, there’s no need to read on. If you’re still interested, I’ll lay a little groundwork here before I outline some things remedial you can do to combat excess water retention. Almost all out-of-the-bag soils retain a considerable amount of perched water after they have been saturated. Each individual soil formulation will retain a specific height of perched water unique to THAT soil. No matter what the shape or size of the container - height, width, round, square …… the height of the PWT (perched water table) will be the same. You can fill a 1" diameter pipe with a particular soil or a 55 gallon S-shaped drum with the same soil, and both will have exactly the same PWT height.
Let’s do some imagining for the purpose of illustration. Most peat or compost based soils retain in excess of 3 inches of perched water, so lets imagine a soil that retains 3 inches of perched water. Also, imagine a funnel that is 10 inches between the exit hole & the mouth and is filled with soil. Because we are imagining, the mouth is enclosed & has a drain hole in it. In your minds eye, picture the funnel filled with a soil that holds 3 inches of perched water, and the soil is saturated. If the funnel is placed so the large opening, the mouth, is down, you can see the largest possible volume of soil possible when using this container is saturated, the first 3 inches; but, turn the funnel over and what happens? We KNOW that the PWT level is constant at 3 inches, but there is a very large difference in the volume of soil in the lower 3 inches of the funnel after it is placed small end down. This means there is only a small fraction of the volume of perched water in the small-end-down application vs. the large-end-down. When you tip the funnel so the small end is down, all but a small fraction of the perched water runs out the bottom hole as the large water column seeks its 3 inch level in the small volume of soil. In a way, you have employed gravity to help you push the extra water out of the soil.
You haven’t affected the DRAINAGE characteristics of the soil or its level of aeration, but you HAVE affected the o/a water retention of the container. This allows air to return to the soil much faster and greatly reduces any issues associated with excess water retention. OK - we can see that tapered containers will hold a reduced VOLUME of perched water, even when drainage characteristics, aeration, and the actual height of the PWT remain unchanged, but we don’t and won’t all grow in funnels, so lets see how we can apply this information PRACTICALLY to other containers.
Drainage layers don’t work. The soil rests on top of drainage layers, then the water ‘perches’ in the soil above - just as it would if the soil was resting on the container bottom. Drainage layers simply raises the LOCATION where the PWT resides. But what if we put a brick or several bricks on the bottom of the container? Let’s look at that idea, using the soil with the 3inch PWT again. Let’s say the brick is 4x8x3 inches tall, and the container is a rectangle 10x12x12 inches high. The volume of soil occupied by perched water is going to be 10x12x3, or 360 cubic inches. If we add the brick to the bottom of the container so the height of the brick is 3 inches, it reduces the volume of soil that can hold perched water, so for every brick you add (4x8x3=96) you reduce the volume of soil that can hold perched water by 96 cubic inches. If you add 3 bricks, the volume of soil that holds perched water would be 360-288, or only 72 cubic inches, so you have reduced the amount of perched water in the container by 80% ….. quite a feat for a brick.
Your job though, is to be sure that what you add to the bottom of the container to reduce the volume of soil that can hold perched water doesn’t create stress later on when the planting has matured. Be sure the container has a large enough volume of soil to produce plants free from the stress of excessive root constriction. You don’t want to trade one stress for another.
How else might we ‘trick’ the water in the container into leaving? Let’s think about the following in 2 dimensions, because it’s easier to visualize. If you look at the side view of a cylindrical or rectangular container, you see a rectangle, so imagine a cylinder or rectangle 10 inches wide or 10 inches in diameter and 8” deep. Both side views are rectangles. Now, draw a horizontal line 3 inches above the bottom to represent the level of the PWT. Remember, this line will always remain horizontal and 3 inches above the bottom. Now tip the container at a 45 degree angle and notice what happens. The profile is now a triangle with an apex pointing downward and the base is of course the line of the PWT 3 inches above the bottom. Can you see there is a much lower volume of soil in the bottom 3 inches of the triangle than in the bottom 3 inches of the rectangle? The PWT line is level at 3 inches above the apex, so by simply tilting your containers after you water, you can trick a large fraction of the unwanted perched water to exit the container. Sometimes it helps to have a drain hole on the bottom outside edge of the pot, but not always. Only when the location of the hole is above the natural level of the PWT when the pot has been tilted does it affect how much additional water might have been removed.
On the forums, I’ve often talked about wicks, so I’ll just touch on them lightly. If you push a wick through the drain hole and allow it to dangle several inches below the bottom of your container immediately after watering, the wick will ’fool’ the perched water into behaving as though the container was deeper than it actually is. The water will move down the wick, seeking the bottom of the container and will then be pushed off the end of the wick by the additional water moving down behind it.
A variation of the wick, is the pot-in-pot technique, in which you place/nest one container inside another container with several inches of the same soil in the bottom and fill in around the sides. Leaving the drain hole of the top container open allows an unobstructed soil bridge between containers. Water will move downward through the soil bridge from the top container into the bottom container seeking its natural level; so all of the perched water the soil is capable of holding ends up in the bottom container, leaving you with much better aeration in your growing container.
The immediately above example employs the soil in the lower container as a wick, but you can achieve the same results by partially burying containers in the yard or garden, essentially employing the earth as a giant wick. These techniques change the physical dynamics of water movement and retention from the way water normally behaves in containers to the way water behaves in the earth. Essentially, you have turned your containers into mini raised beds, from the perspective of hydrology.
What I shared doesn’t mean it’s a good thing to use water retentive soils, simply because you have tricks to help you deal with them. For years, I’ve been using highly aerated soils and biting the ‘water more often’ bullet because I’ve seen the considerable difference these durable and highly aerated soils make when it comes to plant growth and vitality. Many others have come to the same realization and are freely sharing their thoughts and encouragement all across the forums, so I won’t go into detail about soils here.
It should also be noted that roots are the heart of the plant, and it is impossible to maximize the health and vitality of above-ground parts without first maximizing the health and vitality of roots. Healthy roots also reduce the incidence of disease and insect predation by keeping metabolisms and vitality high so the plant can maximize the production of bio-compounds essential to defense.
The soil/medium is the foundation of every conventional container planting, and plantings are not unlike buildings in that you cannot build much on a weak foundation. A good soil is much easier to grow in, and offers a much wider margin for error for growers across the board, no matter their level of experience. But regardless of what soils you choose, I hope the outline here provides you with some useful strategies if you DO find yourself having to deal with a heavy soil.
Is there a listing of acid loving and non-acid loving plants. I think part of my problem is acidity. After I started using lime (as you suggested), I found a big difference in many of my plants. I use lots of peat moss.
Acid-loving plants prefer a lower pH, but the term 'acid-loving' can be misleading. Some plants are only able to grow in acidic soils because it makes one or more nutrients the plant has difficulty assimilating more soluble and thus easier for the plant to acquire. Or, some plants have trouble limiting uptake of certain elements that are less available under acidic conditions, and need those conditions to limit availability. pH in MINERAL soils, that is in the gardens/beds/landscape, is more important than it is in the highly organic mediums we usually use in containers. If you are able to limit availability of nutrients the plant has a tendency to absorb too much of, or supply the nutrients in soluble form the plant has difficulty assimilating, it hardly matters what the pH of the container medium is. If you supply nutrients in a form that is soluble in the soil solution, and in a ratio favorable to the other nutrients, the plant will have no difficulty with uptake - as long as you keep the roots system healthy.
okay! So I've read most of this thread--at least Tapla's responses :) -- and I still have 2 questions:
1. will the 5:1:1 mix only last for a year? I really don't have the time, space, money to invest in the gritty mix (which from tutorials, seems a bit hard to make, e.g. finding all the materials, sifting, etc.) So, can I do anything to the mix (if, in fact, it only lasts for a year) to make it last longer? Some plants of mine, I think, don't need to be repotted every year necessarily. So, I guess, at most I'd like to get the 5:1:1 mix to last 2 years tops.
2. people seem to complain a lot about the tendency of peat to go hard (so they use coco-peat instead). First, as I see it, I'm not sure why anyone would let their plants go bone dry before watering...But more importantly, is this true? I've never experienced it, and I've also heard that dunking your plant in water for a couple of minutes will help reverse this. What's the consensus?--Is peat hard to use if it dries out?
1) ... will the 5:1:1 mix only last for a year? ... can I do anything to the mix ... to make it last longer? Made well, it should remain structurally sound for at least 2 years or longer. The issue is usually that the plant becomes root-bound to the point it needs repotting before soil collapse becomes an issue. Also, when roots have fully colonized the soil and the plant is fully established, unless you really work at over-watering, soil collapse is less of an issue because the plants roots actually become a part of the soil structure, helping to minimize the impact of a soil that is breaking down..
2. people seem to complain a lot about the tendency of peat to go hard (so they use coco-peat instead). First, as I see it, I'm not sure why anyone would let their plants go bone dry before watering...But more importantly, is this true? I've never experienced it, and I've also heard that dunking your plant in water for a couple of minutes will help reverse this. What's the consensus?--Is peat hard to use if it dries out? Peat and coir both have a tendency to compact and get hard with age. Peat has the additional tendency toward hydrophobia - that is to say, it becomes hard to rewet. I've seen plants (pines) in peat based soils that were so compromised by the soil that the soil was actually harder than the plant's roots, and had to be removed with a chisel. Coir, has some inherent issues that make it unsuitable as a primary fraction of a container soil. It's high pH precludes the use of dolomitic (garden) lime as a liming agent, and it's K content is extremely high, and as such needs accounting for in a fertilizer program if you are looking for best results. Most commercial operations that include coir as a fraction of their container media limit its presence to a small fraction, usually less than 10%.
Dunking your plants in water for an appropriate time (say an hour) can help to more evenly saturate a dry root mass, but it won't reverse compaction.
The gritty mix is my choice for houseplants because it holds little or no perched water, depending on how careful you are about how you make it. The 5:1:1 mix doesn't offer as much potential as the gritty mix under normal conditions, but it still stands head and shoulders above anything you're likely to come across that's base on peat. Also, if you use some of the tricks I've outlined to eliminate all the perched water from the 5:1:1 mix, it should perform almost as well as the gritty mix.
For the most part, getting away from the excess water retention inherent in peat/compost-based soils is going to increase your plant's potential and make it a whole lot easier for you to bring along consistently healthy plants.
Hi Al, I was reading your comments about repotting vs potting up. Are you saying in your chart that all plants should be repotted every year? Or potted up every year? And if not all plants, how do you know which should be and which shouldn't? Specifically, a variegated Clivia, and also a variegated split leafed Philodendron. I do use Mychlorothiazai sic. on my plants after repotting. Is this not a good idea? Just a boost for their roots. Thanks so much for your help.
I don't want it to be a 'one size fits all' sort of deal, but the growth of plants, and their vitality/health, begins to be affected at about the point where roots become congested to the point where the root/soil mass can be lifted from the pot intact. Some might argue that there are desirable effects attributable to purposely allowing some degree of root congestion, and that is entirely true, but those effects don't negate the fact that there is still a negative impact on growth and vitality.
If you have a plant that you want to bloom more profusely (for some plants), grow more compactly, have smaller leaves/shorter internodes/grow at a reduced rate, SOME root congestion might be desirable; but root congestion from the plant's perspective is never a good thing.
I have hundreds of plants in containers, many of them bonsai and plants growing on as future bonsai, but I also have a number of houseplants/succulents that get fully repotted every 1-5 years, depending on their inherent vigor and growth rate. The increase in growth rate after a full repot/rootwork is easily seen not only by observing the notable increase in growth rate, but in the plant's physiology as well. For instance, I once repotted a Madagascar palm for a friend that had been in the same container for an unknown length of time - well over 5 years, though. Its growth habit was very stout - the plant grew wide, but not very tall. After it was repotted, it doubled it's ht in the first year, and WHEN it was repotted will forever be recorded in the plant's physiology - the spines on the plant before the repot grew very close together (height), after the repot, there was 5-10 times the vertical distance between the spines, indicating the plant was extending at 5-10 times the rate prior to the repot.
Most growers would consider the plant's reaction as a growth spurt, but in reality, it wasn't a 'spurt' at all. It was the result of my eliminating a limiting factor (tight roots) so the plant could return to growing much closer to its genetic potential. We can never make a plant grow at beyond its potential, but we can certainly limit its potential easily enough. What defines us as growers is our ability to recognize and eliminate limiting factors to the greatest degree possible. We can further put our skills on display by using limiting factors to achieve a desired result, but embracing limitations for any reason doesn't negate their effects.
Clivia is one plant that can be potted up until it begins to obviously wane. Rinse all the soil you can from the fleshy roots, then pot up. When the middle of the plant starts to grow weakly, divide the plant, using starts from the outside of the plant mass for your new containers and discard any unneeded plants from the center.