The following is very long & will be too boring for some to wade through. Two years ago, some of my posts on another forum site got people curious & they started to e-mail me about soil problems. The "Water Movement" article is an answer I gave in an e-mail. I saved it and adapted it for my bonsai club newsletter & it was subsequently picked up & used by a number of other clubs. I now give talks on container soils and the physics of water movement in containers to area clubs.
I think, as container gardeners, our first priority is to insure our soils are adequetely aerated for the life of the planting, or at least, in the case of perennial material (trees, shrubs, garden perennials), from repot to repot. Soil aeration/drainage is the most important consideration in any container planting. Soil is the foundation all container plantings are built on, and aeration is the most important block in the foundation. Since aeration and drainage are inversely linked to soil particle size, it makes good sense to try to find soil components with particles larger than peat and that will retain their structure for extended periods. Pine bark fits the bill nicely.
The following hits pretty hard against the futility of using a drainage layer in an attempt to improve drainage. It just doesn't work. All it does is reduce the amount soil available for root colonization. A wick will remove the saturated layer of soil. It works in reverse of the self-watering pots widely being discussed on this forum now. I have no hands-on experience with these growing containers, but understand the principle well. There are potential problems with wick watering that can be alleviated with certain steps. Watch for yellowing leaves with these pots. If they begin to occur, you need to flush the soil well. It is the first sign of chloride damage.
Since there are many questions about soils appropriate for containers, I'll post by basic mix in case any would like to try it. It will follow the Water Movement info.
Water Movement in Soils
Consider this if you will:
Soil need fill only a few needs in plant culture. Anchorage - A place for roots to extend, securing the plant and preventing it from toppling. Nutrient Sink - It must retain sufficient nutrients to sustain plant systems. Gas Exchange - It must be sufficiently porous to allow air to the root system. And finally, Water - It must retain water enough in liquid and/or vapor form to sustain plants between waterings. Most plants could be grown without soil as long as we can provide air, nutrients, and water, (witness hydroponics). Here, I will concentrate primarily on the movement of water in soil(s).
There are two forces that cause water movement through soil - one is gravity, the other capillary action. Gravity needs little explanation, but for this writing I would like to note: Gravitational flow potential (GFP) is greater for water at the top of the pot than it is for water at the bottom of the pot. I'll return to that later. Capillarity is a function of the natural forces of adhesion and cohesion. Adhesion is water's tendency to stick to solid objects like soil particles and the sides of the pot. Cohesion is the tendency for water to stick to itself. Cohesion is why we often find water in droplet form - because cohesion is at times stronger than adhesion, water’s bond to itself can be stronger than the bond to the object it might be in contact with; in this condition it forms a drop. Capillary action is in evidence when we dip a paper towel in water. The water will soak into the towel and rise several inches above the surface of the water. It will not drain back into the source. It will stop rising when the GFP equals the capillary attraction of the fibers in the paper.
There is, in every pot, what is called a "perched water table" (PWT). This is water that occupies a layer of soil that is always saturated & will not drain at the bottom of the pot. It can evaporate or be used by the plant, but physical forces will not allow it to drain. It is there because the capillary pull of the soil at some point will equal the GFP; therefore, the water does not drain, it is "perched". If we fill five cylinders of varying heights and diameters with the same soil mix and provide each cylinder with a drainage hole, the PWT will be exactly the same height in each container. This is the area of the pot where roots seldom penetrate & where root problems begin due to a lack of aeration. From this we can draw the conclusion that: Tall growing containers are a superior choice over squat containers when using the same soil mix. The reason: The level of the PWT will be the same in each container, with the taller container providing more usable, air holding soil above the PWT. Physiology dictates that plants must be able to take in air at the roots in order to complete transpiration and photosynthesis.
A given volume of large soil particles have less overall surface area in comparison to the same volume of small particles and therefore less overall adhesive attraction to water. So, in soils with large particles, GFP more readily overcomes capillary attraction. They drain better. We all know this, but the reason, often unclear, is that the PWT is lower in coarse soils than in fine soils. The key to good drainage is size and uniformity of soil particles. Large particles mixed with small particles will not improve drainage because the smaller particles fit between the large, increasing surface area which increases the capillary attraction and thus the water holding potential. Water and air cannot occupy the same space at the same time. Contrary to what some hold to be true, sand does not improve drainage. Pumice (aka lava rock), or one of the hi-fired clay products like Turface are good additives which help promote drainage and porosity because of their irregular shape.
Now to the main point: When we use a coarse drainage layer under our soil, it does not improve drainage. It does conserve on the volume of soil required to fill a pot and it makes the pot lighter. When we employ this exercise in an attempt to improve drainage, what we are actually doing is moving the level of the PWT higher in the pot. This reduces available soil for roots to colonize, reduces total usable pot space, and limits potential for beneficial gas exchange. Containers with uniform soil particle size from top of container to bottom will yield better drainage and have a lower PWT than containers with drainage layers. The coarser the drainage layer, the more detrimental to drainage it is because water is more (for lack of a better scientific word) reluctant to make the downward transition because the capillary pull of the soil above the drainage layer is stronger than the GFP. The reason for this is there is far more surface area in the soil for water to be attracted to than there is in the drainage layer.
I know this goes against what most have thought to be true, but the principle is scientifically sound, and experiments have shown it as so. Many nurserymen are now employing the pot-in-pot or the pot-in-trench method of growing to capitalize on the science.
If you discover you need to increase drainage, insert a wick into the pot & allow it to extend from the PWT to several inches below the bottom of the pot. This will successfully eliminate the PWT & give your plants much more soil to grow in as well as allow more, much needed air to the roots.
Uniform size particles of fir, hemlock or pine bark are excellent as the primary component of your soils. The lignin contained in bark keeps it rigid and the rigidity provides air-holding pockets in the root zone far longer than peat or compost mixes that rapidly break down to a soup-like consistency. Bark also contains suberin, a lipid sometimes referred to as nature’s preservative. Suberin is what slows the decomposition of bark-based soils. It contains highly varied hydrocarbon chains and the microorganisms that turn peat to soup have great difficulty cleaving these chains.
In simple terms: Plants that expire because of drainage problems either die of thirst because the roots have rotted and can no longer take up water, or they starve to death because they cannot obtain sufficient air at the root zone for the respiratory or photosynthetic processes.
To confirm the existence of the PWT and the effectiveness of using a wick to remove it, try this experiment: Fill a soft drink cup nearly full of garden soil. Add enough water to fill to the top, being sure all soil is saturated. Punch a drain hole in the bottom of the cup & allow to drain. When the drainage stops, insert a wick several inches up into the drain hole . Take note of how much additional water drains. This is water that occupied the PWT before being drained by the wick. A greatly simplified explanation of what occurs is: The wick "fools" the water into thinking the pot is deeper, so water begins to move downward seeking the "new" bottom of the pot, pulling the rest of the PWT along with it.
Having applied these principles in the culture of my containerized plants, both indoors and out, for many years, the methodology I have adopted has shown to be effective and of great benefit to them. I use many amendments when building my soils, but the basic building process starts with screened bark and perlite. Peat usually plays a very minor role in my container soils because it breaks down rapidly and when it does, it impedes drainage.
I'll give two recipes. I usually make big batches.
3 parts pine bark fines
1 part sphagnum peat (not reed or sedge peat)
1-2 parts perlite
controlled release fertilizer
micro-nutrient powder (substitute: small amount of good, composted manure
3 cu ft pine bark fines (1 big bag)
5 gallons peat
5 gallons perlite
1 cup lime (you can add more to small portion if needed)
2 cups CRF
1/2 cup micro-nutrient powder or 1 gal composted manure
3 gallons pine bark
1/2 gallon peat
1/2 gallon perlite
handful lime (careful)
1/4 cup CRF
1 tsp micro-nutrient powder or a dash of manure ;o)
I have seen advice that some highly organic soils are productive for up to 5 years. I disagree. Even if you were to substitute fir bark for pine bark in this recipe (and this recipe will far outlast any peat based soil) you should only expect a maximum of three years life before a repot is in order. Usually perennials, including trees (they're perennials too, you know ;o)) should be repotted more frequently to insure vigor closer to genetic potential. If a soil is desired that will retain structure for long periods, we need to look to inorganic components. Some examples are crushed granite, pea stone, coarse sand (no smaller than BB size in containers, please), Haydite, lava rock, Turface or Schultz soil conditioner.
I hope this starts a good exchange of ideas & opinions so we all can learn.
A product called magic cloth or magic mop works very well. It is a super-absorbent man-made chamois (100% rayon). Cut in strips, it absorbs & moves water quickly. I've also had good luck with the woven plastic ties that are used to keep citrus bags (oranges, grapefruit) closed until we buy them. Both are effective.
Wicking away the PWT is helpful in many cases, but not a cure-all for soil that drains poorly. It is especially helpful when plantings are young & roots have not colonized the lower portions of the container. Later, when the plants have developed to the point that they need more frequent watering, simply remove the wick & more water is available to the plant after each watering.
Yes, if you're familiar enough with its use & recommended concentration(s). Though it is also helpful in a healthy root environment, it is most valuable when there are root issues like poor aeration or one of the rot fungi beginning to increase in #'s.
H2O2 has an extra O atom (compared to H2O) in an unstable arrangement. It's the extra atom that makes it useful in horticultural applications. Generally, we're not concerned with aerobic forms of bacteria normally occurring in container media or on roots, but various fungi & poorly aerated soils are often a problem.
Since H2O2 is an unstable molecule, it breaks down easily. When it does, a single O- atom and a molecule of water is released. This O- atom is extremely reactive and will quickly attach itself to either another O- atom forming stable O2, or attack the nearest organic molecule.
Many disease causing organisms and spores are killed by O, the free O- H2O2 releases is extremely effective at this. H2O2 can help eliminate existing infections and help prevent future ones. The free O atom can destroy dead organic material (i.e, leaves roots) that are rotting and spreading diseases.
Reduced O levels and high temperatures encourage both anaerobic bacteria and fungi. When plants growing in soil are treated with H2O2 it will break down and release O into the area around the roots. This helps stop the O from being depleted in the water filled macro-pores until air can get back into them. High O levels at the roots will encourage rapid healthy root growth and discourage unwanted bacteria/fungi.
I know it comes in several different strengths. I'm thinking 3%, 5%, 8% and 35% solutions. Cheapest is 35% which you dilute (to 3%) by mixing 1:11 with water. Plastic or glass is best to store it in, & the container should be opaque to prevent light degradation. If three-liter pop bottles are available in your area they are ideal for mixing and storing H2O2. Once you have it mixed at 3% (or start with 3%) mix it at the rate of 1-1/2 tsp/gallon of water as a cutting dip & up to 2-1/2 tsp/gallon to water containers with on a regular basis. Start at the lower concentration and increase concentrations gradually over a few weeks.
H2O2 in high concentration is a powerful oxidant & will bleach skin white & oxidize almost anything it contacts - quickly. This includes living plant tissues, so be careful with it if you use it. A solution that's too strong can kill any organic molecule it contacts.
Bacteria colonizing the pot bottom will quickly munch through the cotton fibers, causing it to rot to pieces in no time. Better to use a synthetic shoelace or a tie from an orange bag. I bet a strip of pantyhose would work, too.
Fold in half over the end of the blade of a straight-slot screwdriver or similar. Push up into drain hole several inches. It will remove most or all of perched water, but remember - it's not a cure for lack or aeration. ;o)
Al, thanks. I had read on another site that terry cloth or any type of cotton was a good wicking material. But I believe you. I don't buy oranges by the bag, so I'll try shoelaces.
Explain to me why removing the excess water would not solve the aeration problem. I'm going to start adding H2O2 (thanks for the formula) to the container water, but I have far too many containers to think about repotting all of them.
Another question: I have some herbs growing very happily in a round, shallow planter. I'm sure the roots are all in the PWT, but this is the second year those herbs have been growing in it, and they are really doing well. I have curly parsley, flat parsley, chives, rosemary and basil, all doing great. You think maybe the pot is so shallow that evaporation is preventing saturation? These plants tend to droop if I don't water daily, so I know it's drying out quickly.
And another question: I have an R/O system in the house. Would it be worth the trouble to collect filtered water from the indoor tap to water all the outside containers?
Thanks for all your help. I read all your posts with great interest.
Thanks, Al. All of my plants are in containers, and trying to keep this one barely damp, this one dry, and that one moist is very difficult as I can't handle a hose so my DH has been doing the watering. I am wondering if it might solve at least part of my problem if I water them a couple of times a week with the water containing H202, giving the roots shots of oxygen.
You started this thread by saying your comments could be boring. NOT! I found it fascinating, and I really think that my plants will be healthier, thanks to you.
Excess water: If soil is retaining too much water, it's a sure bet that macro-pores are virtually non-existent (compaction). Removing the water in the PWT will not resolve the compaction issue to any great degree. It really depends on how good (or bad) your soil is.
Please don't think I'm suggesting you repot anything, or even change what you're comfortable with. I only offered the information so those that don't have much knowledge of soils or water movement could start putting things together & perhaps incorporate some of the things they learn, not just from me, but from discussions following the post as well. ;o)
Herbs: Yes, I think you nailed it. In building my soils, I try to consider things like container size, how many plants, sun/shade, etc. and make the soil so it will need watering once per day in the hottest part of summer. As long as you provide nutrients & don't allow the plant to dry completely, a soil that requires watering daily will outperform soils that can go two days, three days, or even longer between waterings. Technically, evaporation isn't preventing saturation, it still occurs, but roots that are in saturated soil, but dry inside of a day (on a regular basis) will show little in the way of ill effects from the temporary lack of aeration. Extend the time to a day & 1/2 in the hottest part of summer, & one of the root rots are likely to take hold. Funny part of that is, the plants will wilt & you'll be tempted to over-water, which only compounds the problem.
Water: Tough question w/o knowing particulars. Do you have municipal water? know the pH of it? Alkalinity level (it's different from pH in case you wondered)? Find out? What kind of soil are you growing in? My first inclination is to say yes, it's worth it, especially if you're as particular about your containers as I. If you find the pH of your water is higher than 8.5 at any time, it would be worth it. Our water here is surface water from Lake Huron, which is usually lower in pH than ground water. After obtaining an analysis from our municipal supplier, I discovered that our water ranges from a pH of around 8.1 all the way to 10. I remember how I struggled 10 years ago before I acquired a reasonable working knowledge of soil chemistry. I think I would have problems with the pH of my water if I hadn't paid attention to business & learned ways to work around nutrient problems. If I had the opportunity - I'd try it for a couple of months on at least a portion of my containers. It could make a huge difference, or non - no way to tell w/o looking into it more or experimenting. ;o)
Hi, Mike! Good to see you! Decided to take you up on your invitation & come over to Dave's to hang out. Still learning how this site works, but am enjoying it very much. Thank you for your consideration. ;o)
You're accurate in your thinking that multiple wicks are no better than one. Also, when considering only drainage & discounting any evaporative benifit that multiple drain holes offer, there is no advantage in having multiple drain holes in pot bottoms as long as the container bottom is level.
This gives me an opportunity to offer a tip on how to improve drainage during periods of prolonged rain (if your soil drains slowly). Under these conditions, drain holes at the container bottom and close to the outer edge are helpful and will allow you to tilt your container to improve drainage (technically, it's not improving drainage, only taking advantage of physics to drain unwanted water from container soil). When a container is tilted, the perched water table remains at the same depth. If we take an example of the PWT at 4 inches in a container, if we tilt the container at a 45* angle, the PWT shifts so that it is horizontal and 4 inches from the lowest point of the container. If you picture this in your mind, you will see there is much less saturated soil at the container bottom. I employ this method frequently on recently planted material with no roots in the container bottom to take up excess water. I also use it on bonsai material that doesn't appreciate wet feet (pinus, juniperus, etc). To prove its effectiveness, water a container thoroughly & wait for water to stop draining from drain hole. If you tilt the container (even with the hole at the center) substantial additional water will drain from your container(s). In imagining this picture, you can now see why some holes near the edges on problem containers can be helpful. With holes in the center only, there is a "dead" area between the drain hole and container edge/bottom that cannot drain when containers are tilted.
Al, I use municipal water and it is very hard. I would guess the pH is very high, but I'm going to call and find out. Thanks for that suggestion.
I am still full of questions, and so happy to find someone to answer them. I hope you don't get tired of answering them.
Please talk to us about size of container vs. size of plant and root mass. I think I've already learned enough from you to know the answer: too big leaves too much soil without any roots to take up water and perched water content is greater. ???
Also please comment on the following potting experience: I purchased 24 little hosta divisions with small leaves and roots ('Golden Tiara') and proceeded to pot them up in small clay pots to grow them out. Well, I ran out of small pots toward the end and put the last 6-7 eyes crowded together in a slightly larger pot. That was about 8 weeks ago. Today, the crowded hostas are growing vigorously, and the individually planted ones have grown very little by comparison. The leaves on the crowded ones are at least 5-6 times larger than the single ones. The difference is beyond significant. The difference is huge. Do you think that this is a soil saturation issue, or is there perhaps some other phenomena at work? I would have thought the result would be just the opposite. ???
Container size - Very small plants can be grown in very large pots with very fast soil, but even plants in small pots can suffer from a slow soil. Roots are not eternal, even in ideal soils. They die & regenerate at an amazing rate. The older roots are, the tougher they are & more impervious to cultural extremes. The all-important fine hair roots are always the first to succumb to adverse conditions - too little/too much water, too hot, too cold, too much or too little of this/that. This slows plant development drastically. I often get mail asking why "my plants aren't doing anything - they're not growing - just sitting there." In most cases, maybe 80 - 90%, the problem can be traced to root issues & a slow soil.
I'm not sure what you meant about "too big leaves"? As plants grow, the roots are always able to support foliage unless something occurs to upset the balance of roots:shoots. This can occur from mechanical injury, temperature extremes, pathogens, or lack of water. Most often, in containers, it's too much water. Roots deprived of 02 begin to die within hours. This is why roots are often unable to penetrate the lower parts of containers with slow soils. Without seeing the size of the pot/plant combo & gaging how highly aerated your soil is, I can't say what's ailing the hostas. My guess is that you're correct in thinking there are root issues with the small plants in individual pots. It's not unreasonable to think that the plants in the crowded pot are able to use up the water that saturates a smaller amount of soil much faster. This allows air (O2) into the soil, which is needed for proper root metabolism and kills root rot pathogens . When next you water, another charge of fresh air is drawn into the pot as water is used.
Plants that are crowded into a pot can exhibit what appears to be normal growth for quite some time, but here is what occurs: Roots occupy an increasingly higher percentage of the container. Soil in the root mass becomes very compacted, or roots themselves become a part of soil structure & soil is washed from roots out drain holes. Watering/nutrient supply becomes an issue in both cases. As roots continue to grow against each other, there is a girdling effect going on, nutrient flow is disrupted & often specific parts of the plant will suffer or die. The most reliable way to determine if your plant needs a repot is by noting extension. E.g., in trees it is easy to determine. If you look at leaf bundle scars, you are able to see exactly what branch extension is from year to year. When extension is decreasing - repot. Immediately, you will see an increase in branch extension in the coming year, & if soils are good, it's likely in the second year as well. In the third year it is likely the extension will diminish, indicating a repot is again needed. Through the whole cycle, leaves are likely to appear perfectly healthy, so try not to allow healthy looking leaves to deter you from a needed repot. More herbaceous plants exhibit similar lack of extension while sporting healthy looking leaves, but it a little more difficult to detect.
Very good post! I had wondered why the excess water comes out of the containers when you tip them. Never been much on a drainage layer in the bottom, I use a very light mix because of the climate I live in.
As you can see, I'm no fan of "drainage layers" in container bottoms. Not only are they ineffective, but often detrimental.
I'll argue the science regarding why not to use them and why they do not improve drainage, but never argue when the reasoning is to lighten containers or economical (as in cannot afford to buy enough soil to fill containers).
Thank you all for the kind words - much appreciated.
Thankyou for the technical information. You have explained the science very well and I sure didn't understand the why's till now.
I have been using the peanuts to take up space and keep things light. I learned my lesson the hard way by trying to move a way too heavy pot.
This was fascinating and I learned a lot. But am a little overwhelmed. I have a lot of containers that I fill at the bottom w/overturned pots to keep them lighter. But, can you distill your information to what you think are the most important points, given that parameter?
I just can't quite wrap my mind around all the info and then figure out exactly what to put into practice. However, I am doing away with the drainage layer in my smaller pots. It will be a pleasure to not purchase and wrestle the bag-o-rocks.
Linda - if the inserted pot is conical in shape, there will be soil that occupies the space between the two container walls. This soil will act as a wick and drain the PWT from the soil above the overturned pot. You can also achieve the same results by growing in a shallower or smaller pot and using a wick to remove most excess water in the PWT.
Wicks are also great when they are employed to temporarily chance the container physics. Fill a container to near the top with soil and add a plant. If the soil remains wet for too long. because of an out of balance relationship between container size/ plant material size/ soil choice, you can insert a wick in the drain hole to help remove the extra water until roots have colonized the entire container. Then, simply remove the wick to extend periods between watering.
I spend lots of time on another container gardening forum site and help lots of people from all over develop soils for their container needs. This weekend, I have received at least 12 e-mails about soils. One was from Brussels and another from Antwerp. Whatever I write and whenever I'm asked to distill something or pick the most important point to consider in container growing, it is ALWAYS, without fail, that: In order for your plants to grow at full potential, you must insure drainage and aeration will be guaranteed in your soil as long as you intend the planting to remain viable. In container culture, you can change all the primary cultural requirements (light, water amounts, nutrient supply, temperature, etc.) but you can do little or nothing about drainage/aeration after the planting is made. Air (at the roots) is just as important as water to plant vitality.
Tabasco - Thanks for the welcome. I think I've been around since last Jun or Jul, but have kept a pretty low profile. Why don't you pick a topic you're wondering about & we'll all talk about it. I sure don't know everything, but I might be able to contribute something. ;o)
First, I think you can say 'GW' and 'gardenweb' on this site. (At least I do!) (-: And name any other site, too.
And I read your (interesting) posts over there, but, I don't post there because I was once 'bounced' and would rather be here anyway.
Well, I am doing experiments with my Amaryllis in pots--nothing conclusive since I am not scientific--and may have a few concepts to discuss (after I kill them all!)
And I am getting ready to create a raised bed for vegetables and I found your thread on your new raised bed and will study that and no doubt have questions about that.
And we are talking about the soil conditions for Siberian Iris (not in containers) on the Iris Forum and I am wondering about your potting mix concepts and how they might relate to garden soil... maybe Siberians don't really like all that compost but would prefer some sand...?
Do you know how a lay person/amateur finds out about Soil Science on the Web? Is their a University/Ag School that specializes in it with a good web site? Lots of different opinions among the random web sites...
My garden is very muddy today and I am worried about it.
I'll go right down your post & comment on what I can. It's funny you'd mention Amaryllis. Up-thread, I mentioned a discussion with a grower in Antwerp. Chef Michel. Of course it took me a couple of messages to determine that Michel was Michael and not Michelle, but I'm off the track now. I bring this up because a good part of the discussion was about the Amaryllis he was growing in a passive hydroponic set-up. It was really interesting & the plants looked perfectly healthy. He had maters, peppers, and lots of other interesting things in a set-up he made himself. A handy guy.
Raised beds are very close to growing in the garden, but with better drainage, so much of what you learn about container growing will not apply. You can use a soil in raised beds that would drain far too poorly to even consider in containers. You can also take good advantage of compost and sand if it pleases you because it will not impact drainage aeration like it does in containers.
Of all the Irises, siberica is one of the easiest to grow. They are like potatoes or blueberries in that they really like water, but won't tolerate wet feet. A fast draining soil that you can water often will keep them from rotting. A tomato fertilizer or one with a low N content is a good choice.
"Do you know how a lay person/amateur finds out about Soil Science on the Web?" Read read read, then pay attention to what you are seeing in your own plants & what they are trying to tell you. I have no formal education other than HS, but my interest in bonsai and container culture has kept me studying whatever I find about soils and plant physiology for a good number of years. I also seek out educational opportunities through the several plant-related/garden clubs I belong to and travel to various functions that offer good speakers. I always go with a list of technical questions that have been bothering me & am persistent enough to usually get them answered.
Don't worry about the mud in the garden. God has it under control and your worrying will not help. ;o) Resist the urge to work the soil until you find that when you pick up the soil and squeeze it in your hand, then release it, it crumbles like chocolate cake. If you say that would/could never happen, you have work to do and it looks like organic matter.
A 5 year old soil from a raised bed. Notice the tilth.
tapla, am glad to see you are still here as this thread started so long ago. I have a question concerning using hydogen dioxide in killing the spores of certain fungus. I had a bad outbreak of pythuim last fall in the pansies ( this pythium was resistent to the fungicide Subdue-which I had never seen before , but know it can happen because we all use Subdue first when treating pythium and phytopthera.) and was looking at various ways of treating it. I used Oxidate as a drench (its 27% and the treatment was 64 oz/50 gal water). I was not impressed with its ability or lack thereof in killing the spores because the pythium kept on going and there was already a treatment of Truban as well as Subdue-all full strength-so it had help in the soil to start with. I was also isolating like crazy. I was told that this hydrogen dioxide only had the ability to kill spores on contact on top of the soil, or on any part of the plant above the soil. That once it was put in the soil, it lost its ability to kill-that the particles of the soil compromised its killing potential. So it would be useless with pythium or phytoptherea as they are down in the soil. What do you think-have you any knowledge or experience treating these fungus with hyrogen dioxide? Would love to hear from you about it. Thanks
Terry - I have never read anything scientific on this question. I have asked scientists about the use of H2O2 as an anti-fungal, and a temporary soil oxygenator for O2 stressed roots. Their replies were something along the lines of what you alluded to above, but not that it was a soil-surface sterilizer only. My observations (though purely anecdotal) do not support that either. H2O2 is probably considered a topical because it reacts with (oxidizes) the first organic molecule it contacts. Common sense tells us that a portion of the chemical, mixed with water, will perc through the soil before contacting other molecules.
I have used H2O2 to water my indoor plants during the over-winter period for nearly two years now. I use 1 oz of 6% solution I have diluted from 35% food grade per L. of tap water. I have observed no problems with rot fungi during that period, even in plants where soil conditions would cause me to expect a problem to come calling (some plants are over-wintered, badly in need of repots due to lack of time on my part) collapsed & soggy soil being one. I also have noticed better growth and vitality, increased resistance to insects, and better color. Given some of the shallow containers my plants are in (shallow containers have a very high % of saturated soil and are more difficult to keep rot and soil-insect free) I should expect some rot issues and soil-insect presence, but have noted none, unlike in past years.
I cannot attest to whether H2O2 might be effective in eliminating an infection of either pythium or phytopthera, but it appears to have effectiveness at preventing fungal spread. Again, this may well be scientifically refuted, and what I observe may have basis in another cause/effect relationship. I'm usually quite careful about what I attribute things I observe to, but I am comfortable in my belief that including H2O2 in my watering program is compatible with and an aid to my growing methodology.
Thanks Al for your considered reply. Am thinking that I should at least water my houseplants with it-as much as I underwater them, they need a break!
It was a plant pathologist that gave me the info about not being effective in the soil. I guess I should assume that it makes a better preventive than a solution if I get pythium or phytopthera.
All comes back to watering huh? I tell people that its the hardest job in the greenhouse, and the most important.
Terry - My interest in container gardening is an outgrowth of my pursuit of bonsai. An interesting story: Those that travel to Japan to pay to serve as apprentices of bonsai masters are always relegated to what seems to most to be the very menial task of watering - only. The masters recognize that learning exact watering techniques is a prerequisite to achievement in bonsai. Only after many months of practicing watering under watchful eyes is the apprentice allowed to progress to the more "glamorous" tasks that include handling the master's trees. Watering along with the related aeration and drainage are extremely important to container culture, as you know.
My project this weekend was to be filling and planting my 2 whiskey barrels and 1 ammo box! What a streak of luck that I found this thread and the Big Container Gardening thread first! Thank you all for the invaluable expertise and experience. Looks like a shopping trip first for a drill, screen cloth, wicking stuff, roofing asphalt ... OMG!
I have found this thread to be very useful. I printed it out and have read it several times to absorb the information. Now I have a few questions.
At our summer place we have four large whisky-barrel type containers. Often we are not there for 4-5 days at a stretch, and the plants suffer if there is no rainfall. These are mostly annuals and some tubers (begonias or dahlias), so their roots typically go down less than a foot.
From Al's discussions here, it seems reasonable that, using his mix (recipe above), I could thoroughly soak the medium to increase the height of the PWT to just under the root area and then expect that, over the week, capillary action would pull the moisture from below up to the roots of the plants. This is assuming the mix, and only the mix, fills the pot. All have drainage holes, with optional saucers.
My questions: Would this work? Should I use the saucers? Should I add a wick? Is there any way to prepare the 'system' for a downpour during the week which might alter the level of the PWT?
Also, I was under the impression that the decomposition of wood/bark particles consumes nitrogen. Is this correct, and, if so, does this have any impact on the plant growth? Or does the controlled-release fertilizer compensate for this?
I'm planning to experiment with this over the summer. thanks to everyone participating in the discussion.
You must use a soil or arrange some means of irrigating that insures your plants will not die from lack of moisture during extended periods between waterings. The PWT will be consistently the same ht when soil is at container capacity (this is the measure of water after soil has been completely saturated and has just stopped draining). You cannot increase the ht or volume of perched water by supplying extra water. During a downpour, the water in the PWT will remain at a consistent ht, or possibly briefly increase in ht during the rain, only to quickly return to its normal ht when it stops. From there, the ht of the PWT will steadily decrease as the plant uses water from the soil or it evaporates, until more water is supplied. Perhaps the use of polymer crystals like Soil Moist would be of some help in your case?
Since all bark is rich in lignan (as opposed to cellulose, like in sapwood), and conifer bark is highly suberized (Suberin is a lipid sometimes referred to as natures waterproofing for trees), it's very difficult for decay organisms to cleave the hydrocarbon chains in conifer bark. As a result, it breaks down very slowly. It is fairly easy to compensate for N tie-up in your bark based soils as long as you are already aware that you'll need supply extra N. I have found it effective to use fertilizers with a higher first number (N) and I especially like supplementing full strength doses of soluble 20-20-20 with a simultaneous full strength dose (in the same water) of 5-1-1 fish emulsion. This has been very effective on woody plants & plants grown for foliage. On blooming plants, I often use a bloom promoting fertilizer like 10-50-10 as long as foliage is nice & green. I generally watch the color of the older leaves on a plant as indication of a need for N. N is a mobile nutrient and they yellow first as the plant robs N from them to translocate to newly emerging leaves.
You will almost surely need to supplement your crf with some sort of additional nutrient program. This is especially true when growing in a fast soil. Try to be sure your soils contain the minors (micro-nutrients) too.
If that didn't answer your questions, please let me know.
Al, thanks for this great information, I make my own potting soil and have thought it was a little "heavy" Your recipe is perfect. In place of the peat moss in your recipe I use my original potting mix which is 1/3 peat moss, 1/3 compost and 1/3 rotted leaves (I have 3 areas where I dump my leaves on a 3-year rotation. These areas have the leaves spread out to a depth of about 2 feet. At the end of the third year I rake off top layer of leaves and use the rotted material underneath in my mix) I have already made and used one batch following your directions and am very pleased with the result. Thanks again. Charlie
I use pelletized dolomitic lime. I use crushed granite (turkey grit) extensively in my soils for woody plants, but find it unnecessary in short term soils (display or veggie plantings) where perlite is much less expensive & entirely adequate.
This year, I'm experimenting with gypsum as a Ca source & will occasionally use Epsom salts for Mg.
Turface on left, crushed granite on right. Disregard soil. It's from my raised beds and would hold too much water to be suitable for use in containers.
Pine bark fines are small chunks of pine bark that vary in stages of decomposition from partially composted to raw & uncomposted. They usually come in 2 or 3 cu ft bags & are quite inexpensive. They are often sold as mulch, or soil conditioner, so you need to look for them by product description, not by a particular product name.
Lime is a Ca (calcium) source - usually always deficient in container soils.
Regular lime is calcium carbonate, CaCO3. There are other versions, including dolomitic lime (calcium magnesium carbonate) or hydrated lime (calcium hydroxide). All will raise the pH. This is necessary in some cases because the peat and pine bark in the mixes above is fairly acidic, with pH readings as low as the 4 range. Most peat-based commercial mixes have some sort of lime to neutralize the acidity of the peat.
I use dolomitic lime. My reading leads me to conclude that it is superior for two reasons. First, it contains the magnesium which is sometime deficient in container mixes. Second, it acts more slowly and gradually than, for example, hydrated lime. I adjust the amount of dolomitic lime depending upon the pH requirements of the plant and upon the other ingredients of the mix. If I'm using coconut husk chips instead of pine bark fines, I use less dolomite, because the CHC is closer to neutral pH than the pine bark. If I needed a really acidic mix, like for a Miracle Fruit tree, then I could use pine bark fines and peat and leave out the lime entirely. (I don't have a Miracle Fruit tree yet, but that's my plan!)
I saw Happy's note on the other thread and I would add the following. I use essentially the same recipe that Al gives above, with minor modifications. If I have a plant that is a water hog, I use coconut husk chips (CHC) instead of the pine bark fines. The CHC holds more water. Here is a link I wrote on the preparation of CHC: http://davesgarden.com/forums/t/607678/ Since I started that thread, I have started adding 1 part perlite to my mixes. So essentially it's 3-4 parts CHC, 1 part peat, 1 part perlite, plus the additives. CHC is supposed to break down more slowly that pine bark as well.
Oops, I see that the lime question was (at least partly) answered by Tapla above. Sorry Al. ;-)
My thanks to Demstratt for telling me about this thread,and to Al for starting it.I haven't had time yet to read all the info here,but sure will be using some of the suggestions here in my containers from now on.
Wow . What great information Tapla and Stressbaby has shared with us. Thank you both for sharing your knowledge with us.
I read somewhere were basket lined with coconut husk can increase salt bulid in soil? If this true, wouldn't it be true with coconut husk in soil?
Patti, coconut husk chips often contain a considerable amount of salt...not surprising given the distribution of the coconut! For this reason it is necessary to rinse the chips prior to use. I soak and rinse the chips at least 3 times. On the final rinse I add Epsom salts, magnesium sulfate. The magnesium serves to displace other undesirable positively charged ions, a process called "cation exchange." Without this step, magnesium deficiency can occur, I have experienced this with some citrus. Some people also add calcium nitrate, but this compound is not as readily available and I have had no difficulty using the Epsom salts alone.
I am not aware of anything that would suggest that CHC, once rinsed properly, contributes to more salt buildup than any other growing medium. I hope that answers your question. This is a Jaboticaba growing quite happily in CHC.
Thank you for taking the time to explain this all to me. I appreciate the education. We are never to old to learn.
PS: Beautiful plant you have there too. :O) Do you use wicks Stressbaby?
Rose, I will only rarely use a wick. The last time I used a wick was a year ago when I got a citrus tree just before going on vacation and I didn't have time to repot. I didn't trust the person watering the greenhouse not to overwater the tree, so I put a wick in and the tree did great.
The perched water table in a CHC medium is negligible, nearly zero.
Thanks, Al and all who posted, especially Debi who sent me the link. I needed this information to be more successful with container planting. I will now print it out and use it.
Al: My DH made two large wooden "tomato boxes" and I'm curious if a length of nylon stocking placed from the top to the bottom hole (there are many holes) would be beneficial right from the first stage of planting. Thanks again.
If you're asking if it could be helpful as a wick - the answer is "yes", it could be. It's not necessary that the wick extends all the way to the top, only into any area of soil that contains perched water. For the wick to be useful, it should hang below the container bottom or be in contact with soil or a surface that will drain excess water away from the wick (as in an inclined surface). The number of holes in the bottom of a container makes nearly no difference where drainage is the issue - 1 hole or a 100 makes no appreciable difference so long as the 1 hole allows water to drain (unclogged).
A wick might be helpful in the early stages of the immature planting before roots have colonized the container to help remove excess water from soil. Roots need an O2-rich environment to remain vital. Since O2 disperses about 10,000 faster in air than in water, it is necessary to remove water from the lower reaches of the container for roots to function properly. When the planting matures and uses water at a rate that requires you to water daily, then you can remove the wick, which will then have the effect of extending intervals between waterings.
I hope I understood your question and answered it to your satisfaction. If not, please ask again with a little more detail.
Ohh - it will probably work long enough before it breaks down, but I prefer Fiberglas window screen (or a plastic mesh you can buy at hobby shops for needlepoint application) - it's effective, reusable if you prefer, and very inexpensive. I'll send you some if you like, or you can buy a roll at any home improvement store for a couple of bucks. I've never had a clogging issue with the soils I use.
There are a few supplements available that are specifically compounded to deliver micro-nutrients. Usually, in the powdered or granular micro-nutrient mixes you'll find the macro-nutrients (majors) magnesium, calcium and sulfur, along with the micro-nutrients (minors) iron, boron, zinc, copper, manganese, molybdenum, chlorine, cobalt, and nickel.
Two reliable and commercially available powdered chemical mixes are Micromax (insoluble) and STEM (soluble). Earth Juice and fish/seaweed emulsions are a couple of reasonable organic sources for some of the minor elements too.
I have done some experimentation (keeping loose controls in place) with Superthrive, and have found it useful for stimulating the growth of new roots on cuttings and recent repots only, and have perceived no value in it as a tonic or general plant stimulant. I have the description/results of what I saw in the experiments if any are interested in seeing it posted.
The question of the value of Superthrive as a miracle tonic for plants is often bandied about in horticultural circles. Several years ago, after reading claims that range from “I put it on and my plant, which had never bloomed, and it was in full bloom the next day” to “It was dead - I put Superthrive on it and the next day it was alive and beautiful, growing better than it ever had before”, I decided to find out for myself. If you look for information on the net, you’ll find the manufacturer’s claims and anecdotal observations, so in want of anything that resembles a control. Though my experiments were far from scientific, I tried to keep some loose controls in place so that I could make a fair judgment of its value, based my own observations. Here is what I did, what I found, and the conclusions I made about my use of Superthrive.
On four separate occasions, I took multiple cuttings. In each case the group of cuttings were taken from the same plant. The plant materials I used were: Ficus benjamina, (a tropical weeping fig) Luna apiculata (Peruvian myrtle), Chaenorrhinum minus (a dwarf snapdragon), and an unknown variety of Coleus. In each instance, I prepared cuttings from the same plant and inserted them in a very fast, sterile soil. Half of the cuttings were soaked in a Superthrive solution of approximately 1/2 tsp per gallon of water. The other half of the cuttings were watered in with water. In subsequent waterings, I would water the “Superthrive batch” of cuttings with a solution of 10 drops per gallon and the others with water. The same fertilizer regimen was followed on both groups of cuttings. In all four instances, the cuttings that I used Superthrive on rooted first. For this reason, it follows that they would naturally exhibit better development, though I could see no difference in vitality, once rooted. I can also say that a slightly higher percentage f cuttings rooted that were treated to the Superthrive treatment. I suspect that is directly related to the effects of the auxin in Superthrive hastening root initiation before potential vascular connections were destroyed by rot causing organisms.
In particular, something I looked for because of my affinity for compact branching in plants was branch (stem) extension. Though the cuttings treated with Superthrive rooted sooner, they exhibited the same amount of branch extension. In other words, internode length was approximately equal.
As a second part to each of my “experiments”, I divided the group of cuttings that had not been treated with Superthrive into two groups. One of the groups remained on the water only program, while the other group was treated to a 10 drop per gallon solution of Superthrive. Again, the fertilizer regimen was the same for both groups. By summer’s end, I could detect no difference in bio-mass or vitality between the two groups of plants.
Since I replicated the above in four different trials, using four different plant materials, I’m confident in drawing some conclusions as they apply to me and my growing habits or abilities. First, based on my observations, I have concluded that Superthrive holds value for me as a rooting aid, or stimulant if you prefer. I regularly soak the soil, usually overnight, of my newly root-pruned and usually bare-rooted repots in a solution of 1/2 tsp Superthrive per gallon of water. Second, and also based on my observations, I don’t bother with its use at any time other than at repotting. No evidence was accumulated through the 4 trials to convince me that Superthrive was of any value as a “tonic” for plants with roots that were beyond the initiation or recovery stage.
The first ingredient listed as beneficial on the Superthrive label is vitamin B-1 (or thiamine). Growing plants are able to synthesize their own vitamin B-1 as do many of the fungi and bacteria having relationships with plant roots, so it's extremely doubtful that vitamin B-1 could be deficient in soils or that a growing plant could exhibit a vitamin B-1 deficiency.
Some will note that I used more of the product than suggested on the container. I wanted to see if any unwanted effects surfaced as well as trying to be sure there was ample opportunity for clear delineation between the groups. I suspect that if a more dilute solution was used, the difference between groups would have been less clear.
It might be worth noting that since the product contains the growth regulator (hormone) auxin, its overuse can cause defoliation, at least in dicots. The broad-leaf weed killer Weed-B-Gone and the infamous Agent Orange, a defoliant that saw widespread use in Viet Nam, are little more than synthetic auxin.
Great information, thanks! I'm going to make great use of it, but I have a question for you that is specific to my region. It's hot, hot, hot here in the summer, and dry, dry, dry. I can see a pot with that soil mix drying out very quickly (in a day) and being difficult to rewet. What about substituting vermiculite for the peat?
Hi Lynn ;o)
You may be surprised to learn that sphagnum peat holds about 90% water by volume at saturation and gives it up over a fairly even curve until it becomes so tightly held in the media it is essentially unavailable to plants at about 30 kPa when it still retains about 30% water. #2 and #3 vermiculite both hold about 71-72% water at saturation and give it up over similar curves until they reach about 30 kPa with about 28% remaining as unavailable to plants.
What this means is that when peat and vermiculite reach about 30% water content, they both hold water so tightly that plants cannot extract it from the media. However, peat initially holds about 28-30% more water by volume than vermiculite, so it is actually a better choice than vermiculite insofar as water retention is concerned, especially since their availability curves are similar.
You may wish to consider adding some polymer or starch granules specifically packaged to sell as a moisture retention aid, or include some rock wool in your soils. Rock wool holds about 90% water by volume at saturation and gives it up over a steep curve, making almost all water held available at tensions as low as 5 kPa. It also does not become hydrophobic when it dries down like peat. I think I would retain the peat in the mix and replace a portion of the perlite with rock wool.
Happy - You should be able to buy or order granular rockwool from any hydroponics supplier. You can buy an absorbent type or a hydrophobic product. Both increase aeration and drainage while only the absorbent type increases water retention.
Remember guys (Happy & Pirl), Lynn lives in a very arid region of the country & the need to use a highly water-retentive soil there is going to be far more urgent than where you live.
The soil recipes I suggest are just good starting points. If you intend to build your own soils, you'll need to get a feel for how they will perform and amend them appropriately to suit your plant material and growing habits. It may or may not be appropriate to use absorbent rockwool in your soils, but I am quite certain that you can build a perfectly suitable soil for your area with nothing exotic or hard to come by.
My reason for asking, Al, is that the pots will be in the courtyard and it's probably an effective zone 8 there. I think the heat from the stone would dry out the pots faster than if they were placed in the shade or within gardens, on soil or on grass.
Last summer our little ten day heat wave dried out every pot and only a few plants survived even though I watered them daily.
I have noticed that I need to change the potting medium mixture a bit with the wick method, as the first round of experimental wicks is indeed drying the pots out, which this time of year is good, however when the heat turns up will need to adjust to some of the above recommendations.
I have been experimenting with Lava Sand the past few years, and it has a great capability of moisture retention at certain temperatures. From what I've studied about and observed from it's use is it's ability to facilitate a greater nutrient absorbtion rate by the roots.
By "lava sand", are you referring to zeolite or specifically the product ZeoPro? It's purported to have some kind of extraordinary CEC, but from recent conversations with some whose judgment I trust: "... I didn't see results that made feel I can't do without this." There's nothing stopping you from trying it out & letting us know your findings though.
You may also wish to consider substituting a calcined clay product for any perlite in your soils. Calcined clay aggregates (such as Turface MVP) have an excellent CEC capacity (if it means anything, up to 12 me/100 cc) and 40-50% internal porosity. This translates to good water holding capability (over perlite since it has 0 usable internal porosity) and a whole lotta cation attachment sites @ more than 13 acres of surface area per lb of aggregate.
Build your soils and select container sizes so that you can go at least 24 hours between watering in the heat of summer and when the planting is mature. If you do this, you could well be over-potted early in the grow season when the planting is immature & roots have not colonized the container completely. If such is the case, then is the time to use a wick - until you need to water more frequently than you are willing to. At that point, remove the wick to increase irrigation intervals.
Finer sands will increase water retention and can provide enhanced drainage in some soils, but they generally do so at the expense of aeration. What I consider appropriate-sized sand for hort applications is going to be about 1/2 BB size or larger. I've used screened products: coarse silica, crushed granite, pumice, and Turface all extensively with very good results, but only find them necessary in soils that need to be formulated for extended life.
As far as the sand you refer to "facilitating a greater nutrient absorption rate by the roots, I would have to say that is probably technically not accurate. It may be true that it could prove beneficial by holding onto nutrients that can readily go into solution and then be absorbed by the plant, but it won't likely increase absorption over and above what any adequate nutrient supplementation program would. Plants absorb water and dissolved nutrients when the moisture (matrix) tension of soils is lower than the cellular tension and is probably unaffected by what soils are comprised of (structurally speaking - pH assumed appropriate) so long as air/water/nutrients are present in appropriate ratios.
It can be an effective way to water, helping to reduce some of the soil compaction that you find from top-watering and reducing over-saturation at container bottoms. You should be careful about allowing fertilizer salts & dissolved solids in your water from building in soil due to ongoing evaporation (this will be especially evident in the top 1/3 of the soil volume). Top-watering helps prevent this build-up, and you can lessen its effects it by flushing soil with an occasional copious top-watering. Do this by watering well & then returning a little later to flush the soil with water enough to approximately equal the soil volume.
Oh - it probably doesn't matter much if you apply that much water, but it does tend to increase compaction, which is a valid reason to water via wicks to begin with. The description I gave is well-supported in bonsai culture, where watering plants is made into a very exacting science, so I'm pretty comfortable offering it up as a guideline. Copious top-watering also tends to leach nutrients along with accumulated metal salts, increasing the necessity for additional fertilizer applications. I know Bob already knows all of this, so I offer it mainly for the other readers. By reading his posts, I'm sure he's pretty well satisfied with his methods and has this well-covered.
While I'm here though, I might offer a tip on how to water a container thoroughly and efficiently:
Wet the soil thoroughly over the entire surface (I almost always try to keep foliage dry), using what you gauge to be the approximate maximum volume you can apply w/o water draining from the container bottom. Wait 10 minutes while the water also disperses laterally through the container and water again so that about 10 - 15% of the total volume used on that container drains from the bottom. This method effectively allows accumulated salts to go into solution and flushes them from the container in draining water when done on a regular basis. Of course, this is assuming your soil is well-aerated and drains well enough to allow this kind of watering.
Tapla: You write: "This method effectively allows accumulated salts to go into solution and flushes them from the container in draining water when done on a regular basis." But I am lazy and just allow the plants to drain into a saucer. I assume that defeats the purpose of what you are describing -- you would want those accumulated salts to go down the drain each time, yes? Not that I will change my ways, but I guess I need to feel even more remorseful!
Lolol! Yes - you should be wracked with sobs of sorrow after you find out how right you are! ;o)
Prolly not the biggest deal we have to worry over though. Once you're aware of the possibility of problems, a little effort goes a long way. A quick empty & rinse of the drain saucer would be helpful ...
(this will be especially evident in the top 1/3 of the soil volume) How does the salts build up only in the top 1/3 when the wick only wets about 2/3 of the way? I like keeping the top of the soil dry by wick watering due to Gnats or fungus.
The entire volume of soil will draw water upward through capillary action. The greatest amount of evaporation will occur in the portion of soil with the greatest exposure to air. This will be the soil's surface & the area just below, where air circulates freely. Since the greatest evaporation occurs in the upper part of the container, the highest concentration of residual metal salts (both from fertilizers and dissolved solids in irrigation water) will occur there as well.
Please note that when media feels dry to the touch, it does not necessarily mean that it is dry. You cannot detect moisture in most media by "feel" at saturation levels less than about 35%, but this does not mean that water migration and evaporation is not occurring. Even wick-watered containers that always feel dry to the touch at the surface will eventually exhibit white deposits from metal salts build-up at the soil's surface.
Al- You are amazing :-) I want to come garden with you! I once posted a question about soil, and you explained it in the same easy to understand detail you have done here. I am going to try your mix- so far I have been pretty disappointed with most of the bagged stuff I have bought. I am going to try the wick with some of my houseplants, as here in Philly there is nothing outside right now other than my perennials and my ash bonsai, all waiting patiently for spring. And that salt deposit that you mention- I have a devil of a problem with that in my water here- I get them routinely, and have to get rid of it. I'm on a right wavelength though, as I've already been flushing the soil and occasionally rinsing my saucers and bowls that my housplants sit in- just made sense to me, although its a job since I have many, many houseplants. Watering is a chore sometimes, but those plants bring such joy to me that it makes it all worth it. Thanks for sharing your wealth of information with us again- take care!
Ohhh gosh - you guys are soo kind. I often get chided from friends for the tendency not to acknowledge such nice compliments because I get embarrassed, so I better tell those that have gone out of their way to offer thanks or encouragement along the way, that I really appreciate your efforts. It makes any effort on my part seem like no effort at all. Thanks to all of you - and to Dave's too, for providing us a place to exchange ideas and learn together. ;o)
I agree. I've learned so much on this thread. Thank you to all y'all with knowledge and experience to share and to everyone with thought-provoking questions to ask!
I have a question about rock wool. I recieved a free sample baggie of small cubes about 3/4 inch square (dry) and have done nothing with it. Should I try to grind it up to use in container gardening? Use as is..in the super duper potting mix described above? Or should I use it to propagate in water, which was I believe the original intent for the product?
Hi, Carol. I'd bet that they are 1 x 1 seed starting cubes. Usually, you would start a seed in/on the cube & when roots appear at the bottom, move it to a larger cube that has been hollowed out and specially prepared to receive the smaller cube or plant in another appropriate medium. I suppose you could reduce the size of the pieces & add it to a soil if you feel there is a need for more water retention in that soil.
I also have this thread linked to the journal. The sand is very dense, so you are right in the fact that aeration suffers, which I have learned in the school of hard knocks the past few summers. In my journal I explain where I picked up the idea of using the sand. You explained what I meant as far as the product allows a greater amount of time for the plant roots to draw nutrients, other than the fast wash of "stuff" going throgh the container. I am convinced once I get the combination correct the "lava sand" will work well. I have had some great success with it in a hit and miss way. Now that you've pointed out aeration, the light bulb clicks on and I have to go and put the latest mad scientist potting medium together!
I am very much interested in trying the calcined clay. I'm sure I'll be able to get this at my favorite garden store, but in case..is this something available at Home Depot or other common places? I have an image of kitty litter...LOL.
Re the journal, you'll have to probably interpolate some of my conjecture in what I'm trying to say.. You say it a bit better than I.
Al, fantastic thread! And bigtime thanks! Also, no need to be embarrassed because you chose to share so much valuable info. I've read, re-read, and use this thread as a great "research and remind me" source for quite a while now!
Love it! I hope this becomes a Sticky at some point in time.
It would be great to "sticky" this thread -- lots of great information here, clearly presented!
I'm using wicks now whenever I repot... I thought that was a great idea! In the winter, most of my pots sit inside on saucers, so the wicks won't help with drainage (although they may permit me to do some bottom watering)... but in the summer, I use little pot stands under many of the pots on the deck, so the wicks would be able to dangle down. (Having the weight of the pot rest on the 3 little feet of the stand isn't very linoleum-friendly, or I'd use them in the winter also.)
Somebody mentioned kitty litter -- why not use (clean) kitty litter? It's just little granules of clay, right? I'm thinking of the cheap stuff from the dollar store, not anything with perfumes or "mystery crystals."
I've got all-day sun on my deck, so I do use polymer moisture crystals in all my pots... when it's less hot, I can skip a day of watering, and even when it's 100 degrees I only have to water once a day (without the crystals, I'd be watering twice a day and plants would still droop).
I know a great place to get bulk quantities (2 lbs, 10 lbs, or even 55 pounds which I just ordered to split with a friend) of moisture crystals: http://www.watersorb.com/index.htm. Even with shipping (included in the price), it's cheaper than buying the containers of "Soil Moist" et al. at the box store or the nursery. "Medium" crystals are the right size for containers. Don't put in more than the recommended amount -- when the crystals expand, your potting mix will heave around, or the crystals will come popping up and over the lip of the container like weird little jello cubes -- a little goes a long way.
Unfortunately, all kitty litter is not created equal. Those that are of appropriate particle size and are fired at temperatures high enough to insure stability when wet are perfectly usable in soils. Those fired at low temperatures will revert to clay and present drainage/compaction/aeration issues in soils.
Thanks for the link on the polymer crystals. I'm adding it to my FAVORITES. ;o)
Yes, both directly (physically) and indirectly (promote bio-activity), but if you are using in any quantity, even though fir bark breaks down fairly slowly, you may need to compensate for some N tie-up with extra N applications.
Since you're asking this question about mineral (garden) soils, it is probably more a question for the Soil and Composting forum; but, unstabilized wood products can tie up nitrogen in the soil and cause nitrogen deficiency in plants. Microorganisms in the soil use nitrogen to break down the wood, making it unavailable for plant uptake. In time, nitrogen is released and again becomes available to plants. This occurs frequently with the incorporation of wood products with a high surface area to mass ratio and fresh (uncomposted) wood products (sawdust, e.g.). If you plan to incorporate wood chips (especially fine ones) you may need to apply nitrogen fertilizer at the same time to help avoid nitrogen deficiency.
Manure's primary shortcoming when considered for use in containers is that it breaks down very quickly, thus inhibiting drainage & aeration. Other problems include the fact that it can be too hot in containers when fresh and often contains plenty of troublesome seeds. I used to use a small amount of composted manure in containers but found it more trouble than it is worth. I abandoned its use in favor of other more reliable ways of delivering the minor elements.
Al using H202 when wick watering the water never seems to go bad (sour) like it does without it added. How long does it last and what does it change to. Seems like it should be used up rather quickly. Does fertilizer neutralize it in any way.
H2O2 has 2 O atoms, unlike water which contains only one. Chemically, it's an unstable chemical compound. Ions with the right potential range for reduction in nutrient solutions act as catalysts for the reduction of H2O2 to H2O. This reaction releases O atoms, providing extra oxygen to the plant roots and improving root function. It also and oxidizes metallic elements, making them more readily available for plant uptake.
As you note, the water doesn't "sour" because the H2O2 reacts with and kills organic molecules that contain catalase.
I wasn't sure about your question - I hope that answered it.
I didn't really mention this because of price, but more because of ingredients. Watersorb's MSDS lists it as "Acrylic acid / acrylamide copolymer". Terra-Sorb's active ingredient is "Potassium Polyacrylamide Acrylate Copolymer". I've seen other polymers that were sodium based, and I'd advise anyone using one of the sodium-based polymers to cease, and avoid them like the plague. One of the last things I want to add to my soil is salt. I'm not so sure that acrylic acid is very beneficial, when it breaks down, either. Terra-Sorb breaks down over about 5 years, into potassium. Seems the best product to use, no?
Interesting point. Though it may not be as important for the plants in container culture, we as consumers might want to think about what we use in the way of water absorbing soil amendments and how we use them. They do persists in the environment & have no nutrient value to flora or fauna!
Some of the "extra-absorbent" characteristics mentioned by manufacturers of polymers are exaggerated, & as bio-degradation occurs these polymers actually reverse their effect and hold moisture so tightly it is unavailable to plants. Soils can usually be designed so forest products (bark), peat, and other organic media components that adequately hold moisture can be used with no ill effects. These products, even in containers, provide the plant(s) some nutrient value & fodder for the micro-organisms that polymers inhibit. Some degraded polymer components even have some of the same effects on mammals as female hormones, which can affect mammalian fertility and potency.
Additionally, and as you alluded to, the polyacrylamides in some garden-grade moisture holding polymers are made from (& contain) the monomer acrylamide, a known carcinogen.
I haven't done any tech reading on the product you mentioned, but when I get the chance, I'll chase it down. Thanks for bringing this subject to our attention.
Al: I had never considered that there could be a down-side to using the water absorbing crystals, though it does make complete sense given that they are not organic -- there is no reason to assume they'd continue to perform the function for which they were designed as they break down. The last thing I would want to do is use a product that is environmentally counter-productive. Do you ever use water absorbing crystals? I have purchsed some plants that need extra moisture, and had planned to boost their soil with some crystals.
I purchased a container of a common brand of the product several years ago & have only used a few teaspoons of it. I have a lot of plants & they're all in even faster soils than I suggest here, so I need to make the watering rounds daily since the greater share of my plants require a frequent drink. You can see that with that kind of attention needed anyway, the product's advertised benefits hold little allure for me.
I'm new here and since all my plants are in containers this is a thread I need. I do have a question and i'm sorry if you've answered this, I sometimes use small rocks in the bottom of my pots- does this really help with drainage?
Thank you- I read that but didn't understanding the wording the first time. I will end up reading this over and over because you sometimes miss things or don't understand till the next time-then you wonder how you didn't "see" it before.
I've got some kind of ivy in a self watering pot. The tips of the leaves are turning brown? Time to change the soil do you think? It's the first plant I got just over a year ago and I'm concerned. Any ideas?
Are the brown tips on new growth or old leaves? If it's on the old leaves it's probably nature at work. There's probably a forum for ivies on DG and maybe those people could give you better answers than I.
Both actually. Thank you for your advice on the forum. It took me a bit to find the right one. I hope someone can help. It was the first plant I got when I moved to TX from AL and it's special:) I'll let you know what I find out. Elizabeth
Just thought I'd post two quotes from the watersorb site...
"With an essentially neutral pH, Watersorb super absorbent polymers will break down into nitrogen, carbon dioxide and water with no residual toxicity."
"Sodium based polyacrylamide was discontinued by all manufacturers over 5 years ago and is no longer available. All polyacrylamide is potassium based."
I know the above quotes are from the folks selling the stuff, so I'm not trying to suggest that's the final answer as to potential toxicity. However, I've never seen any data to support the idea that these polymers break down to produce acrylamide, which could indeed be a hazard.
Sometimes I think things can sound scarier than they are... for example, people will not purchase irradiated ground meat or eggs, because we all "know" that radiation is bad for us, never mind that eliminating bacteria from these products makes them safer and doesn't otherwise change them... In some places, they are using the term "cold pasteurized" rather than "irradiated," and the same products fly off the shelves.
I'm not trying to fan the flames here... if you're not comfortable with a product, don't use it. :-)
No fanning flames here either. I have no wont to debate either the sagacity or ethics of using water absorbing soil products and I agree that it's an individual decision. I hope our comments will prompt some readers to do some broad-based research of their own. I know I always learn something incidental to the subject I'm researching, each time I dig into something.
I tend to use them in the lower 2/3 of the container, partly so that the crystals don't work their way up to the surface of the potting mix as they plump up with water... that seems to happen sometimes, especially if you've put in a few too many crystals... it doesn't do any harm, but it sure looks odd! And like you said, having the crystals form a reservoir of extra moisture down lower in the root zone seems like a good thing.
Most roots are hydrotropic and gravitropic, meaning they will grow toward water and downward. They don't need encouragement, other than making sure there is also ample air in the water holding portions of the container.
Sensor cells in the root cap cause the plant to turn toward water sources in hydrotropism. In gravitropism, a redistribution of Ca in the root cap causes a change in lateral auxin flow, which makes cells on the top of the roots elongate, Subsequently, the roots grow downward.
In light of my last question and your subsequent response describing the tendency of roots to grow downward and toward water, how would these things work? Why would the roots not 'want' to stay at the bottom, where the moisture will be consistently higher than at the top and gravity would have its pull? How can they grow large enough to support a healthy plant with an abundance of fruits? Thanks, as usual.
It probably serves no purpose to offer the technical answer to your question, but if you want to research it, entering the words circumnutation and thigmostimulation will reveal the technical mechanism(s) involved.
All tropisms are not created equal, some being requisites and others tendencies. Root gravitropism is one of the weaker ones, and hydrotropism really has nothing to do with root ability to "sense" a distant water source.
Fine roots lead a precarious existence and their survival/advancement is more of a "good news / bad news" scenario. New roots that tend to grow into inhospitable areas (of a container) die - those that grow into favorable parts of the soil live.
Roots cannot "smell" nor do they seek water/air/nutrients. They tend to grow where the growing is good, which is usually in the top 12 inches of soil where temperature, moisture, nutrients and soil-oxygen are usually most favorable. To underline the fact that roots are opportunistic "absorbers" - There has been recent tendency in hort writings lately to curtail use of the term "feeder roots" because it carries implication the roots are out "hunting and gathering" the necessities of water and nutrients. Roots simply take advantage of the cultural gradient of the surrounding soil, meaning that roots tend to grow where there is a good supply of moisture, nutrients and very importantly soil-oxygen (Here, we can read in plenty of incentive to be sure that our container soils are well-aerated. The water and nutrients are easy).
Summarized: Roots will grow where conditions are best, even if it means a tropism or two has to be trumped by favorable cultural conditions.
I expect they would colonize the entire container with the densest rootage concentrated in the upper 2/3 initially, becoming equally dense throughout as the plant's water needs increase (and cause air to return to the soil more frequently as the planting matures).
The plant itself will act as a wick & help to reduce the o/a volume of water held when the planting is at container capacity. Though I've not used these containers, my initial concern would be disease related issues as water contaminated with soil-born pathogens drips down the stems of the plant. It seems that, by design, that is inevitable.
I just found this thread and found it interesting, not boring! I printed out the thread and haven't gotten all the way through it yet (44 pages) but it is great. The info is going to be very helpful. I do have one question about the pine bark. I live in an area with a serious infestation of carpenter ants and we don't use pine bark. Can cedar bark be used instead and what size is appropriate for the mix.
I'm not sure. The common name "Cedar" covers much ground and includes trees in at least 7 genera I can think of just off the top of my head. You'd need to find out what tree the bark came from and research it for any allelopathic properties (poisonous to plants - like some trees in the Juglans genus). Wish I could help more.
Mixing some diatomaceous earth into a damp soil as you make it would also solve your carpenter ant problem so you could use the pine bark.
There's a wide range of particle sizes that are appropriate. I use the bark at both 3 and 9 o'clock for many soils, but for veggies and flowery display containers, I prefer a product that looks like what's at 12 o'clock.
I followed your recipe, re-potting quite a bit and I must say they are all looking very healthy. I have to make another batch now. Interestingly, as far as looks and feel, it resembles a high grade mix some friends of mine use for their plant business at $10.00 plus dollars a bag wholesale.
Well, like Tapla says you would have to research it to see if it is poisonous to the flowers. I know Walnut trees cause I problem. In the northwest almost everything is cedar. But there are tons of different kinds of cedar. Right here on my property I have many different ones.
In the northwest and CA, fir and redwood bark are readily available and work very well. I grow many things in a soil that uses fir bark as the only organic component. I have a dear friend in CA that I talk to all the time who uses a variation of the recipe above with composted redwood bark instead of the pine. That also works very well.
Tapla and others...thank you so much for this info. It explains why I have had such trouble and wasted so much money on container plantings gone bad!!! I just want to say that judging by the number of questions and responses, this is a very hot topic and you should consider finding a publisher...your way of explaining the chemistry and science of everything is so down to earth and layperson friendly that it is very marketable!!!!
Scheesch - you guys are great, and are literally going to make me blush. Those who know me will know my comment isn't false modesty either. I'm really moved by the positive comments and your thank yous. I can't tell you how much they mean to me. There are lots of other contributors up the thread, plus all the people who perpetuate it by asking questions, that also deserve a pat on the back; so, I'll take a second to thank everyone who contributed their opinions & comments, as well as those asking questions. Thank you for providing me with such a pleasant diversion and a way to have fun.
Help. I tried to buy Pine Bark Fines or any fines at all and couldn't find any bark of the size I understand to be useful. Little nuggets and bigger was all I could locate in either the biggest gardening center near us or Lowes. The best I could find was a product called "Bumper Crop"..the outside of the bag says that the ingredients include bark fines, peet, composted manure and composted oyster shells. The marketing info says: A blend of composted fir bark and forest humus fortified with 15% chicken manure, worm castings, bat guano and kelp meal. pH balanced with dolomite and oyster shell lime. An all purpose pre-fertilized planting and garden soil amendment. Excels as a nutrient rich top dressing and mulch.
This seems like it would be great but doesn't have perlite...is it still advantageous to add this? Also, it is pricy so I would still prefer to find the bark fines. Anyone out there in NYC that has had luck finding the fines? Cheryl
Yes... I realize that but wasn't sure it would still be necessary???
And Al...one more thing. What is "green sand". Gardeners Supply sells it and it says "it is a naturally occurring iron-potassium silicate that contains as many as 22 trace minerals to enhance soil fertility and loosen clay or compacted soil. It will absorb and hold large amounts of moisture in the soil and help proling flower bloom."
How does it loosen compacted soil AND hold large amounts of moisture in the soil? They say it is for veges, flowers and lawns. Cheryl
tapla - what is the difference between controlled release fertilizer and continuous release fertilizer. I'm finding several brands of continuous release but haven't seen controlled release. Would you give me brand name to look for that would be good. I've only searched in Lowes so far but I have plenty of nurseries in my area to check out. And would you also give me the brand name of a micro-nutrient powder that would be good. Thank you so much. We're still waiting on the weather in the northeast to warm up so we can get outside in the garden so I thought I would start getting my supplies ready for the container mix that you suggested. I found the diatomaceous earth on an earlier shopping trip - I'm the one with the ant problem. Thanks again for all of your help and advice.
I hope I don't step on any toes if I chime in here...
Micromax and STEM (Soluble Trace Element Mix) are the micronutrient sources I see used most often.
STEM is soluble in water and can be used as a foliar spray.
Micromax is a powder, released over a period of time as long as 18 months. Finding Micromax has been a challenge for me. I would have expected that somewhere, online, one could obtain a small, 3-5# bag or bottle, but so far as I can tell, such a product is not made. I have only been able to find big 50# bags. Eventually I did find a nursery about 50 miles from here that will sell me a cup at a time.
Cheryl - because of the angular shape of the sand particles, when incorporated into soils it "wedges" between other soil particles & holds them apart or "loosens" them. It's also said to hold about 10 times more water than regular sand, though I'm not sure why. It has to be that the particle's structure has lots of surface area or that they have internal porosity structure that regular sand does not. In either case, this aspect is of no value in container soils as they should already have good porosity and a loose nature. Fine particulates, from a physical perspective, also tend to reverse our efforts th maintain a well-aerated mix.
Chemically speaking, your comments above pretty much cover the benefits of greensand. I'd temper those comments by adding that greensand is extremely slow in giving up it's trace elements. Though a small amount would probably do no harm in containers, I believe there are better sources of micro-nutrients available that do not impact drainage/aeration and that readily release (or slowly if you choose the appropriate product) nutrients for immediate uptake.
Grammy - "controlled" and "continuous" are used interchangeably, with "continuous release" used most often to point out that nutrients are ever available when using a "controlled release" product.
I most often use either Micromax insoluble micro-nutrient granules for incorporation into soils as I make them. I use STEM, a soluble, fine granular with my fertilizer program as both a remedial and maintenance supplement on plants that have no Micromax in the soil or on plants growing in soils in which the Micromax has been absorbed or washed from the container.
If you have trouble finding these products & you feel you want to use them, contact me & I'll put you onto a source.
Hi, Tapla, are you still giving speeches? I would love to attend one of
your lectures. Mind you that I am a beginner with gardening. Please
advise where your next lecture will be. I live in Columbus Oh and am
often in Bluefield Wv.
Oh golly, Confused... - I mainly just loan myself out to local clubs when they ask. I don't actively seek out speaking engagements, nor do I charge for a talk. There's probably more information presented in this thread & some similar threads now running on another forum site than I could ever compress into a presentation that would last an hour or two - and you still have the same opportunity to ask questions we can all learn from. Oh - and plus, there are other minds at work here besides mine, so you get the benefit of conversation as we kick things around. Thank you though. You've made me smile (broadly). ;o)
Well, let's try to stay focused on container soils, though I love all the attention that Rose is getting. :o) It's only fair to the folks who come here for soil & growing information - yes?
I really don't know exactly what she is (not a sedum though - Echeveria, I'm sure). I got her at a big box store for a buck, many, many years ago - maybe 12-15. When she gets too tall, I lop her off & restart the rosette as a cutting. She produced only a single shoot one time, but it withered & died on the stem before I could propagate it. Whatever she is, she's the most feminine plant I have ever seen, and NEVER looks the same from one week to the next.
I've followed this thread with great interest; my brain cannot process all the information. But now it's time to start filling my 15-20 outdoor containers. I empty the soil into my compost pile each fall and start fresh the next spring (I do this b/c I've always assumed that the nutrients have been absorbed, and I don't want the roots of the past season's annuals to be in the soil).
I would like to follow your soil recipe, Al, but I am ashamed to admit that have followed this entire thread w/o knowing what "CRF" is!!! (It is mentioned in the original recipe). Also, when shopping for "pine bark fines", is this the same as commercially bagged mulch?
The bark fines might be found packaged as any number of things. Some are processing larger bark chunks through a chipper to get a suitable size. See the picture above that shows three bark products + perlite. Ideally, what you want is at 12 o'clock, but I use the other bark products for other soils too.
"Soil Conditioner" "Southern Yellow Pine Bark" "Pine Bark Mulch - Decorative Ground Cover" are just a few of the names I've found on packages containing suitable material. I've used pine, fir, and hemlock bark - all with good results.
Partially composted is best. Stay away from products that have lots of sapwood (non-bark woody material) in them. These companies package and distribute an excellent product. You could call to see who/if anyone distributes for them near you.
Mid America Mulch Inc.
Bradenton, Florida #(941) 746-1999
Harbor Springs, Michigan #(231) 347-0077
Partially compost your own for next year in a trash container. Moistened small bark chips & some high N fertilizer will yield a great product, or do it on a pile if you need lots of bark.
I've never had trouble locating it. I've bought it from Meijer, wholesale by the pallet from nursery/greenhouse suppliers, and from an assortment of nurseries. I wish you luck, I'm sorry it sometimes proves difficult to find.
C'mon ovr - we'll mix it onna driveway & u can take it home with u!!! ;o)
Thanks, Al! It's a long drive from MI to MA w/ a truck load of soil!!!
I am growing dahlias in pots this year. To them (I've read) it's the kiss of death to use a high nitogen fertilizer (makes weak, hard to store tubers). Would you make any adjustments to your recipe for dahlias?
Not to the mix itself. I think though, that I'd do a couple of things that most wouldn't do.
First, I'd leave the CRF out of the mix. If I could find a 5-10-10 soluble fertilizer, I'd use that. Instead, I use a 20-20-20 and a 0-10-10 mixed together at half strength. Sometimes I use a 5-1-1 fish emulsion with the 0-10-10 - it just depends on what's handy. I know this works better than straight 20-20-20 or a bloom formula like 10-52-10 or 15-30-15.
Also, I'd fill the container about 1/3 full of soil and add the tuber, barely covering it. Then, I add soil as the plant grows. until the soil is about 1/2 inch from the rim. It makes a strong-stemmed, well-anchored plant.
I can't comment on the effect of high N fertilizers on the tuber condition. I don't see why it would produce a weak tuber, as plants only use what they need (toxicity issues aside), regardless of the amounts of nutrients in soil.
Al, thank you. From what I know of human nutrional needs (a few college courses), our bodies take what we need from water-soluble vitamins (again, toxic levels aside), yet we store excess fat-soluble vitamins in our body fat, to be used later. If we continue to ingest fat-soluble vitamins, the amounts in our bodies can quickly become toxic. I wonder: are all nutrients used by plants water-soluble? Is there a toxic build-up equivalent? Since tubers are next year's "refrigerator" (term from Steve N.) for the plants' nutrituonal needs, does excess nitrogen cause the tuber to break down in storage? I wonder if nitrogen itself doesn't "keep"?
These are just hypothetical questions; no reply needed.
Got this on my watch list. Thanks for all your information!!! Love to read all the info and comments and I refer to it often.
Do you have any info on potting up a tropical Hibiscus plant? I got it Monday at Lowe's and it's in an approx. 6 to10 " pot (not sure right now). I've never grown and/or potted one up before. I only use organic fert., can you give me a good one to use and for the potting mix, would it be any different than 'your basic mixture'?
Well Marilyn, I have a half dozen hardy hibs in the ground & use at least a half dozen tropicals each year in containers, so I have some experience in growing them and coaxing lots of blooms out of them. The soil mix above is very good for hibs, but there is a better mix if you want to talk about it. Let me know.
Hibiscus appreciate a light and coarse soil, similar to that above, mainly for the drainage & aeration they provide, not particle size. Soils that are mainly fine peat tend to compact and hold too much water, resulting in badly aerated roots and rot issues, so remember aeration is particularly important with hibs.
Assuming you'll use a fast draining soil: for best flowering, plan on fertilizing EVERY week with a full recommended dosage while the plant is actively growing. They're pigs & love fertilizer. You'll have to translate these numbers into whatever you can find in organic fertilizers, but I can tell you you'll be hard pressed to keep up with their nutrient needs with organic nutrient supplements. Water soluble formulas can be used with every watering at lower doses if you want, but I find that a pain & weekly is just fine. Most use a "bloom-inducing" blend like 10-52-10 or 15-30-15 on hibs, thinking the extra P will induce blooms, but they don't especially like P. Look for something with a low P (middle number) content. If you could find a soluble 20-5-20, it would be great. Blends high in P like listed above, or even 20-20-20 will produce lots of fine leaves & far fewer blooms. For best vitality, plan on adding some Epsom salts & chelated iron or your organic source of Mg and Fe into your fertilizer program, too.
Potting up is best about now where you live. I treat them like trees & bare-root/root prune every year, but you can score the root mass several times vertically with a razor knife. Pull a few handfuls of roots off the bottom & sides (don't worry - this will not kill or harm this vigorous plant) and pot in the next larger pot. If you're using a very fast soil, you can use a very large pot if you prefer. The plant will grow buck-wild. ;o)
I'll vouch for that.
I use the instructions here in the thread for the soiless mix. My 1.5 inch Hibiscus cuttings I brought back from Hawaii last year are exceeding 6 feet tall. The other, not so tall has been blooming non stop since January- it does need to upgrade to a bigger pot already.!
Marilyn - I grow almost everything I expect to go more than a year in the same soil, or that I intend to root-prune annually or every other year, in a coarse and spare mixture that is 2/3 inorganic and 1/3 pine bark. It retains water reasonably well, and you can adjust that by varying the ingredients. I also grow all my houseplants and succulents in some minor variation of this mix. It will certainly retain its structure for longer than an appropriate interval between repotting (different than potting-up). It consists of:
1 part Turface (I screen mine, but you'll find it unnecessary)
1 part grower grit (crushed granite sold at feed stores as turkey grit)
1 part pine bark
Garden lime or gypsum (whichever is appropriate)
CRF (leave it out for hibs)
elemental sulfur (if appropriate)
I didn't mention this soil because most are unwilling to look for the ingredients, but they all have multiple uses for building container soils and are wonderful amendments to have on hand, once you understand how they affect your soils.
Pirl - I usually use the mix described in the original post for veggies, pretty flowers (garden display container plantings) ;o), or anything else I consider short term plantings. Don't misunderstand - the bark-based soil mix will outlast a peaty mix by far, but I still usually turn the soil into the garden or compost each year & make fresh, - that's just how I am. ;o)
I use a variation of the mix I just described to Marilyn immediately above for all things woody at the first repot. For roses, I would use the mix I described to Marilyn, but add a little more bark & some peat to it; clematis would get the same soil as the roses and I would double pot them, trying to be sure the outer pot was white or light in color (cooler roots); dahlias would go in the original mix (first post).
It doesn't HAVE to be this complicated at all. Almost everything will grow better in the original mix than in a bagged soil. I didn't mention this other mix because the average grower won't want to be bothered with building it, but you guys are asking questions, and I'm just trying to provide the answers w/o regard to what may (or may not) be involved in finding suitable ingredients. I find them extremely easy to come by, but others may not.
I can say this though: If you take the time to find a source for and learn the function of the individual ingredients in a soil, and how to combine them to suit an individual planting, you'll be very impressed with the results - particularly how much easier everything is to care for. The down side is that you'll need to water and fertilize more frequently in any soil I suggest when compared to a bagged soil, but from a physiological perspective, that's a very good thing.
Rose - the echeveria in the 2nd photo up, is growing in 3 parts Turface, 1 part coarse silica sand, 1 part crushed granite, and 1 part pine bark. That's a mix with only 17% organic component, and she's at least 15 years old & marvelously vital. I have other plants growing in 100% Turface - that's NO organic component, and they do spectacularly with only a little attention to making sure I supply the appropriate nutrients in my fertilizer program.
I use Miracle Gro 12-4-8 liquid fertilizer at 1 capful per quart once per week (in a fast soil that drains freely). Cut the dose by half if you use a bagged potting soil. I also supplement with a little Epsom salts every so often (probably every other week, I'd guess) when I think of it.
Turface is a calcined (high fired) clay that is ceramic-like. It's very air and water porous & holds water & nutrients very well (excellent CEC). One pound of Turface has 13-1/2 acres of surface area. It's an excellent soil amendment, used extensively on athletic fields & golf courses because of the properties listed. Additionally, it adds porosity to soils, promotes drainage, and is extremely stable. See Turface at lower left & crushed granite at lower right.
The dark soil at the top is a soilless blend I have in all my raised beds.
Al, the Turface as you describe it almost sounds like either the (can't think of the name) red rock that people use for a dressing in their flower beds, or the lava rock you use in BBQs. OR, are they one and the same?
Come to think of it, why couldn't you use the lava rock in place of the pine bark?
Ohhhhh Marilyn - They're not that difficult at all! We're talking about fine tuning their culture here. You needn't think that you need to provide anything all THAT special. ;o) I'd encourage you to try them with the organic fertilizer you suggested before you edited. I'm sure that under your care they'll flourish.
Jnette - I think "redrock" is crushed red granite & holds very little moisture and would be poor at holding nutrients. Crushed pumice (aka lava-rock) is similar to Turface & is often substituted as long as the size is appropriate. You want the particles to be in the 1/8 inch range.
This is indeed a long and technical post -- and obviously a very thoughtful post -- but I'm wondering if anyone out there is able to sum it up in a paragraph or two. While the WHY is technically significant, I'd simply like to know the WHAT. What's the bottom line? What should I be doing differently? I'm still in the baby-step stage of learning about gardening and this is rather overwhelming.
A LAYMAN'S EXPLANATION
Putting bottom fillers (styrofoam, rocks, ducks) in a container only partially filled with growing medium (soil, dirt, potting mix, etc.) RAISES the water table level in the container, such that the water will pool at that higher level, not drain out completely, and cause your plant's roots to remain shallow and/or begin to rot.
Filling the container completely with your growing medium LOWERS the water table, allows the plant's roots to go deeper to reach the water below, and facilitates proper water drainage through the growing medium, and out the bottom of the container.
Michaelangelo - what you should do is what works best for you. If things aren't working, most often you can look at the relationship between your soil and watering habits. The best advice I can give is : Before you establish a container planting, be certain the soil holds, and will continue to hold adequate air for the intended life of the planting. All other cultural requirements are easily manipulated by the grower - soil aeration is the only one you cannot easily change.
If you have specific questions - ask away. Someone will be able to answer.
I mixed the recipe for one batch to plant my tree peony in and it looked like mostly bark. Did I do it right? It looked funny. Not the planted tree that looked funny. The mix looked funny. The tree looked wonderful planted.
Well, it IS mostly bark. ;o) What size were the chunks? If you're on the rainy side of the mountains, it's likely that an additional part or half part of perlite would be of benefit to you, Jeanette. Tree peonies would also benefit from a healthy helping of Turface or another, similar product you can find in your area called "Play Ball". Another good amendment for woody plants is 1/8 - 1/4 pumice or lava rock. Any of these last ingredients could be used instead of perlite.
Anywhere up to 2 1/2 inches. Not a whole lot that big tho. No, I'm on the East side of the mountains. And, I put about 1/2 a gallon of peralite in it, about the same manure, and probably 2 or 3 gallons of pro-mix. Because of the size of the pot more than anything. That was besides the CRF and lime.
I gotta admit it did look good. Now, what is the Play Ball? Al, do you know anything about a product called "Dynamite"? It is a CRF that activates in the low 50s rather than the low 70s. That, and another product called Enviromoss, a peat moss substitute that starts out as manure and bedding and is the leavings after the Methane gas is used to generate electricity and it's a brown fiber like peat moss but is not hydrophobic and rewets.
These 2 products were the subjects of an article in the gardening section of our newspaper yesterday. I don't know if they are on the market yet tho. And, the way I described them is a very condensed explanation.
I did not realize that about the Osmocotes etc. and the low 70s activation. The temp of the soil here would not reach that until mid June or later. So, the Dynamite would be a real plus for us.
Jnette - I'm unfamiliar with the fertilizer or the "moss" product you mentioned, so I can't really comment. I would want to assess how quickly the "moss" breaks down in soils before I would consider using it. Stability is extremely important in container soils.
Release time varies with different fertilizers and other manufacturers offer blends that release for longer periods than you regularly see - 18 months, e.g., so that part isn't a particular advantage.
I'm not sure how starting a new thread works when this one is a "sticky". Perhaps someone from Dave's has a suggestion.
Confused - A "fast" soil is one that holds lots of air and drains "fast". A "slow" soil is the flip side of the coin - it holds little air, holds water tightly, and drains slowly. Water tables are higher in slow soils and root rot a more frequent issue.
And in case anyone got the impression that I was being critical of the length of Tapla's post, my apologies, but that was not my intention. I'm just looking for the simplified bottom line of what to do because I find all of this very confusing... so thanks again GymGirl and Tapla for giving us that.
A couple of clarifications:
In the past two years I've gardened I've used sytrofoam peanuts. Is the basic idea here to continue to use some sort of drainage bedding but in a larger, deeper pot, or is it about eliminating the bedding entirely? And does this mean water actually drains just as well without the bedding? As you mentioned Tapla, I already add additional holes on the side of my plastic containers.
Is the recipe you’ve given pretty much a good one for Dahlias (grown from seed), peppers, impatiens and herbs? I do think they prefer certain kinds of soil. Many Dahlia sources say to add sand.
Last year I used near-rectangular shaped plastic waste cans for herbs. My books says they should be in 8" deep pots but these waste can pots were 14" deep and the herbs did very well -- so is this an example of how a deeper pot helps with drainage and root health?
Also, is a product that is called "Manure with Composted Humus" (.05-.05-.05) a potting soil? The person at the box store said it is and it kind of looks like one (although it's VERY clumpy) but I'm a bit suspicious. Other than the (.05-.05-.05) there are no labeling details about the product. I don't understand why it's called "Manure with composted Humus" instead of "Compost Humus with Manure."
Thanks again for your clarifications and, in advance, for any further help you can give.
My DH is outside but I'll ask him. I'm sure they came from a book. They're one of two sets of compost bins he built. The umbrella base is there because he sits and chips for three days at a time and needs some shade.
Ohh! Thanks for the b-day wishes, Pirl. Really appreciated! ;o)
OK - Back on track now ...
In the past two years I've gardened I've used Styrofoam peanuts. Is the basic idea here to continue to use some sort of drainage bedding but in a larger, deeper pot, or is it about eliminating the bedding entirely? And does this mean water actually drains just as well without the bedding? As you mentioned Tapla, I already add additional holes on the side of my plastic containers.
Drainage layers are ineffective as an aid to drainage whenever the particulate size in the drainage layer is more than 2.1x the size of soil particles. When the size disparity is great, the water "perches" (like a bird on a branch) in the soil immediately above the drainage layer. The only accomplishment is raising the level of saturated soil in the container and increasing the o/a % of saturated soil. The reason people think it works is because they are growing in a smaller volume of soil, so the soil holds less water by volume than if the container was filled with a soil that drains well. The plant uses the water faster and people say, "Hey - this drainage layer really works!" The fact is, it seems to work because they reduce the o/a volume of soil they grow in.
Is the recipe you’ve given pretty much a good one for Dahlias (grown from seed), peppers, impatiens and herbs? I do think they prefer certain kinds of soil. Many Dahlia sources say to add sand.
Very good for dahlias, and impatiens. Peppers, and particularly herbs would still do fine in it, but they would do better with the addition of something gritty - like Turface, crushed granite, haydite, pumice, large swimming pool filter sand (1/2 BB size) all in around 1/8 inch size. Fine river gravel would work fine, too. They tend to like a more spare soil with extra good drainage.
Last year I used near-rectangular shaped plastic waste cans for herbs. My books says they should be in 8" deep pots but these waste can pots were 14" deep and the herbs did very well -- so is this an example of how a deeper pot helps with drainage and root health?
The 8" suggestion is just a rule of thumb. If the soil is right, you could grow them on a flat rock slab (soil mounded) or in a 1" deep pot. Deeper containers will always have a higher % of unsaturated soil, making them easier to grow in. Easiest of all is a deep container that is wicked to remove unwanted water at the containers bottom.
Also, is a product that is called "Manure with Composted Humus" (.05-.05-.05) a potting soil? The person at the box store said it is and it kind of looks like one (although it's VERY clumpy) but I'm a bit suspicious. Other than the (.05-.05-.05) there are no labeling details about the product. I don't understand why it's called "Manure with composted Humus" instead of "Compost Humus with Manure."
There's no way to tell what it is, but it's meant to go in the the garden or beds & not in a container. I'd also point out that .05 means 5/100 of 1% and should really be written as .0005. Saliva has at least that much nutrient value. ;o) I've seen both sedge peat and black sand sold as composted manure. There are no content % guidelines, so as long as the product contains ANY manure ...
TA - if you are sure it's fired at a high enough temperature that it's stable, you can use it. It would be similar to Turface (also a kiln-fired clay) in its physical properties. The other consideration is size. Ideally, 75% of the particles would be in the 3/32 to 1/4 inch size.
I'd have to agree that users on dialup would have a bit of a time with long threads, such as this one. You could simply start another thread, with the same Subject, appending it as (Part 2). I'm sure a mod would have no problem making the second thread a sticky one.
Ahh, one of the drawbacks to web-based forums. I'm still old school (newsgroups), but consider this site a valuable resource, and it's the only web-based forum that I frequent. =)
Please start a new thread for the dial-uppers out there. I'd hate to see them stop following it and miss out on the great information, because of time constraints! =)
ok, tapla...i have been trying to find the proper proportions for using these ingredients...screened compost (from the city mulch pile), perlite, greensand, and some other nutrients. I'm finding the soil is still pretty slow and heavy. any suggestions on proportions, or additions to make it "faster" and lighter? maybe gypsum? if so how much? I havew a backyard nursery so the plants will stay in containers for quite a while. thanks for helping us all understand this topic.
Well - you're probably not going to want to hear what I have to say, but I'd skip the compost entirely, and the greensand will do nothing to enhance aeration, so I'd leave it out in favor of any one of a number of other sources of micronutrients. A review of the original post, or this one: http://davesgarden.com/forums/t/719569/ will reveal what my thinking is.
Gypsum is prilled & the pellets break down quickly; it will do nothing for aeration or drainage in container soils. Sorry.
You can also place all the ingredients on a tarp. Pull the corners toward you alternately so the ingredients remain on/in the tarp. This method will quickly and thoroughly mix even large batches of soil.
Al, I finally found pine bark fines, and mixed up the "big batch" of your soil in May. My only addition was a jar of water-retaining crystals. I potted up about 12 dahlias, and they are going INSANE growing in this medium! They are far out performing the dahlias that are in the garden. I admit to being a skeptic about a potting soil with all these big chunks, but it does not dry out and pull away from the sides of the pots like commercial mixes do. I find the commercial mixes turn to cement if allowed to dry out, then become hard to re-hydrate.
Oh, Jeanette, c'mon over to the dahlia board!!! There are many folk who only set dahlia tubers in pots, even when they plant them out in the garden- it's called a "pot root" when you do that, and the theory is that the tubers are more easily wintered over- just cut the dahlia stalk and move the container into shelter for the winter.
Yup Jax, that's how it's done. Pirl, the tallest one I have is about 5 feet? But Jax, I don't plant mine in the garden. I could I suppose, but then I would have to dig the pots!! I have mine on my deck.
Some time ago I told them over in the dahlia thread about planting them in pots and they weren't too interested. Mine are so healthy looking and budded but right now they are only about a foot tall not counting the pot, and I pinch them to make them bushy so I don't have to stake them.
LOL, maybe I am making them short without even meaning to.