I'm thinking of declaring war on perched water in small seed-starting cells. Usually seed-starting mix starts out being mostly milled peat. Even if I add coarse Perlite or very coarse sand (very fine gravel), or replace most of the peat with shredded pine bark fiber, it seems that a little seed-starting cell, only 2-3 inches deep, is the container most vulnerable to perched water.
i'm thinking of trays of inserts (72 cells per tray) or "plug trays" with 50, 98 or 128 cells.
The usdual depth is 2.25 inches! Sometimes they are only 1.75" deep!
There's a few rare sizes that are 3.25 or 3.5" deep, say at 18 cells per tray!
And seedling roots must be among the roots most vulnerable to poor aeration, hypoxia or anerobic "drowned" conditions.
So now I'm thinking "wicks".
What small pot could drain better than one that has a big fat wick running through it, top to bottom?
And bottom watering would be a no-brainer if the wick ran right down into the water, and up through the whole soil column.
Eventually I'll go to a craft store and look for yarn or felt or woven fabric that's as water-wicking as possible. Rayon? Polyester? Any suggestions for what kind of yarn, fabric or "rope" would wick best? If it is a fabric, I'll have to cut long strips and fasten them together somehow. But if I wind up having to use fabric, the "bottom wick" or "runs the length of the tray wick" might be replaced b y a sheet of fabric, like a cheapo capillary mat.
If only short lengths of wick are needed, I'll check out "floppy mop heads" at Home Depot and maybe cut those strips in half length-wise.
At first I thought it would be very tedious and annoying to try to thread hundreds of short lengths of wick through the tiny holes in cells, and keep them from falling out before I could set the tray back down to fill it with soil. And how to prop them up while I filled 98 or 128 cells with seedling mix?
Then I thought about weaving a serpentine pattern, with long lengths of yarn, from one cell to the next, up one cell and down the next.
Then use one strand along the bottom of the tray lengthwise, outside the cells, to connect the individual wicks from each six-pack together.
Then, after watering, tilting the tray so that the "lengthwise" wick has some "drop" to it, the better to drain water out of individual wicks, and hence out of the perched water table in each individual cell. Once water dripped from the wicks into a corner of the tray, I could suck it out with a turkey baster.
(I wonder, if I ran the wicks together and then up 2 inches over the lip of a tray, if water would wick UP, and then back down to a container on the floor?)
And, appealing strongly to the "clumsy" in me, when each 6-pack is ready to transplant or "pot up", I could cut the wicks along the bottom of each cell, and cut where they loop from coming up one cell's side to go down the next cell's side.
Then the wicks would serve as handles to let me tug gently on each root ball, to pop it out of the cell! A root ball handle.
My second question (other than "is this just a crazy and pointless idea?") is, to remove perched water, does a wick really need to extend up into the soil? Or would it be just as effective to run the wick along the bottom of each cell only?
One kind of plug tray I would like to "wick" already has two holes in each cell. I could run one long wick along five or ten cells, just weaving in and out of each cell but laying flat along the bottom of each cell. I would still connect those so that one wick would run the length of the tray, to getthe maximum "wick drop" per amount of "tilt" to the tray. (Capilary flow still flows downhill more readily than horizontally, and to "pull" on perched water, I think the wick needs to drop a few inches.)
(But then it would not serve as a "handle" to pull each root ball out of its cell.)
I suppose "well drained seedling mix" would another way to solve the perched water problem, but as soon as I tested my "serpentine pattern" and "root ball puller" concepts with waxed twine, I knew that I just HAD to give this a "Mr. Wizard / Mad Scientist" try.
And I seem not yet to have mastered the "mix that drains so well, that water comes right out every time you water".
Screened perlite + screened pine bark will work wonders for eliminating perched water. Seedlings LOVE the aeration, and the added aeration due to larger particle size solves the PWT/excess water retention issue. Bang. Done. ;o) Your price - you have to water more often ... maybe. It sounds like you already water too much, so your current watering intervals will probably mesh better (with no interval changes) with a more porous soil, so you might see little or no interval change.
I look at wicks as a stopgap measure to be employed when your soil is too water retentive to do the best job.
After you water seedlings in a water retentive soil, you can hold their containers at eye level & move your arm(s)/hand(s) (with the container in it/them) down quickly to waist level. Rapidly reversing the direction upward once it reaches waist level will use 'inertia of motion' to force a LOT of excess water from water-retentive soils, too. The water that is moving downward WITH the soil will tend to want to REMAIN moving downward when you reverse the direction of the container and will keep right on going ... out the drain hole(s).
>> I look at wicks as a stopgap measure to be employed when your soil is too water retentive to do the best job.
That makes sense - part of my motivation is "to go where no one has gone before" ... but if I can get plants started reliably, fast-easy-cheap count for more than a Rube Goldberg science fair project.
I like the inertial un-dampening maneuver!
I think I would havee to find some extra support for my trays, which tned to be flimsy and floppy. I already have enoguh "silly me" stories - I don't need one where I tell how I carefully planted a 128-tray with my rarest seeds, sprinkling each with fine verm iculite and fairy Dust ... then rasied it to eye level ... and snapped it down to wasit level ... and the water kept going ... and so did the soil, seeds and tray!
That said ... what kind of inexpensive material WOULD you use for wicks, if you needed to? Other than special-purpose mail order capillary mats?
My experience with Jiffy pellets and other peat or coconut coir mediums have yielded less than desirable results with problems mainly associated with water. So this year when I got an email from Park's advertising their Original 60-cell Bio Dome Seed Starter on sale I decided to try it.
I was impressed at how easy it was to get it setup and planted. For watering it uses a wicking method which only gives the plants what they need. I will never again use Jiffy pellets.
I used to grow several hundred African Violets using the string wicking method over a reservoir. So when I read about the Bio Sponges and how they wicked only the amount of water the seedling need I was familiar with the process and not afraid to try it. I found the Park's system cleaner and easier to use than the wicking system I used for my African Violets.
This years seed-starting trays got planted without any wacky wicks.
But the pine bark mulch and Perlite (and some coarse vermiculite), but very little Jiffy peat powder, seem to have given it plenty of open structure. It does dry out rather quickly!
I think I should have screened out more of the bigger pieces, it is a little coarse. Next year I'll try for a bit more of the bark fibers and fewer big chunks. Maybe more vermiculite on the very top layer.
I haven't bought a mop head yet, but I saw "rayon batting" in Wal-Mart for $5.30 per square yard and got a yard (thinking to make a capillary mat for 10x21" trays, to facilitate bottom-watering. It's around, oh, 3/16ths - 1/4" thick.
Also, maybe, if the mat presses up through the hole in the bottom of a cell, firmly against the soil, it will drain any PWT out of that cell.
I tested the rayon batting to see how well it wicks: ran a 1" wide strip down into a 1-pint can, over the edge and into a plastic tub in the sink. I thought I would check it in the morning to see if it wicked faster than it evaporated. I glanced at it a few minutes later, and the pint was half-empty!
I re-arranged the dangle, and saw a big, fat drop around once per second.
I think this drains fast enough for most purposes!
At $5.30 per square yard, I think it's less than 90 cents per tray (10"x20.5" bottoms). If I cut it right, I can get 6-7 tray-size mats out of each yard.
A fabric store clerk just told me that cotton - e.g. cotton flanel - is the most water absorbant fabric around.
But I question her expertise with materials not usually used for sewing. When I ran a wick of rayon batting into a har, water zoomed up and over the rim then down into the sink: I almost heard it slupring as it pulled out the last few drops.
I suppose I should set up a race between rayon batting and cotton flannel. Polypropylene, anyone?
The rayon batting almost dissolved after being in the bottom of a tray for a few months. I think I could wash and re-use flannel.
Also, after having some cells sit aorund outside for a while, and transplanting into RBs or potting up, the pine-bark-mix I made seems less open than I thought at first. One batch left the cells pretty soggy at the bottom and not very full of roots.
It's true that any powdery or fine particles very quickly "clog up" the open pores. You really have to use very little "fine stuff" if you want lots of air.
I don;t really know how good my various batches are at pulling water up from the bottom of the tray: I don't bottom-water very much. I still do some top-watering when the surface looks dry. But the rayon batting and cotton flannel do assure that over-watered cells drain down, and under-watered cells suck some up.
To be very sure that all the soil in small cells remains usable by roots, even outdoors where a cell may be over-watered by rain for days in a row, I set the inserts & small pots down on some cotton flannel on top of an open-bottom webbing tray ... then dangled 10-15 inches of cotton wick down from there (trays sitting on a plastic chair).
Probably silly over-kill ... but why not? Maybe it will help drain excess salts, if any, away. I wish the dangling, waving wick would scare away slugs!
Hey Corey, Been busy harvesting now but saw your latest posting here on wicks. Haven't had time to preview DG forums much lately, but I saw this one and decided to see whatís up.
Iíve had some problems with the pepper plants which I potted up in 2.5 gallon plastic pots, using wicks and mostly an inorganic media. I placed these pots in a sunken raised bed hoping to extend the season using covers over the raised beds later in August when temperatures at night drop close to freezing, however the pepper plants never really took off.
I have come to the conclusion that at some point I can move a few of these plants indoors for the winter and see what happens but itís been a really disappointing year for peppers. Next year I plan to plant the peppers in pots again, but I am going back to my well aged cow manure and wood chip fines for my media and forget the wicks.
Wicks may be fine for indoor plants, but I donít believe they served much purpose for my potted outdoor tomato or pepper plants based on what I have seen this season. Simply placing these plants in one of two sunken raised beds with a layer of wood chip fines in the bottom should take care of any perched water problems. That's my take on my wicking excercises for the time being.
Sounds right. In-the-ground means that the whole surface area of the bed is one big wick extending to the mantle, or to wherever your totally imprevious layer (or water table) is.
The capilary-mat-in-a-tray does seem to be doing good things for me indoors, and plants are lasting a long time outdoors in tiny inserts when sitting on mats with dangling wicks.
I was planning to use some big wicks on some raised beds on a slope, but now i think that, depsite the very heavy clay and not enough compost, they already drain well enough for the summer, if I ever water long enough to get them deeply wet. (Raised beds with concrete pavers for walls dry out the edges, and the slope seems enough to drain the bottom. Maybe leaching for 2-3 years has made the clay underlayer more permeable?)
During the rainy season (fall through spring), it might be smart to cover the beds so water runs off the plastic instead of through the soil.
I use this wick watering method for my african violets and over wintering petunias indoors.
Here's what I do (it's slightly "ghetto" lol) I bought a set of used oven racks from a second hand thrift store set over top of the bottom half of two jiffy seed starter kits as the water container (bought at walmart off season). I have the plants in 3oz. solo cups (walmart) with holes drilled in the bottom, a 4" piece of three ply cotton twine for the wick, 1/2" of vermiculite in the bottom of the cups to help wicking and then miracle grow violet soil on top. voila! Happy plants all winter long that are not overly wet but propperly moist and I only have to change the water twice a week which is great because I have 53 little cups all drinking the same water.
After reading your idea I am going to try this method with seed starter cells this spring it would save me a ton of time so thanks!
Clever idea Kristen of adding 1/2-inch of vermiculite to the bottom of your indoor plants. Do you water your plants from the bottom, top, or both?
Reason I ask is because I have been experimenting with various layers of materials in my indoor/outdoor potted hot pepper plants. I use a wicking strip like Corey mentions in the mostly inorganic bottom layer to prevent perched water, and it seems to be working fine. However, the 1/2-inch of vermiculite could possibly allow me to cut back some on the depth of the bottom layer and focus on using more of the upper layer of mostly organics. When the potted plants are left outdoors in warmer weather I top water, and when brought indoors I mostly bottom water.
Some of the science related to some of the recent comments:
You can employ a drainage layer if the material in the drainage layer is no more than twice (2.1X) the size of the layer above, which is why peastone & other large particles are useless as a "drainage layer" below water retentive soils like those from a bag that are based on peat. The drainage layer should be material that will not hold water internally, so vermiculite because of its water retention is less than ideal. Additionally, drainage layer of fine particles (sand) readily pull water from the coarser soil above, but they are counterproductive because they hold more water and less air than the soil you're trying to drain, and essentially reduce the volume of healthy soil available for root colonization.
The healthiest long term arrangement is a container filled with a homogeneous soil mix that is coarse enough to hold little or no perched water that is watered from the top. Watering from the top ensures that accumulating soluble salts are regularly flushed from the soil if you are employing good watering habits, while forms of wick watering ensure all or part of the accumulating soluble salts remain in the soil. While this may not be an issue serious enough to warrant panic, it is limiting and best avoided if possible. Short term wick watering of seed trays would probably present little issue resultant of accumulating salts, but as the term of wick watering increases, so does the likelihood of soluble salt becoming a limiting factor. Remember, in order for a practice to be limiting, it doesn't necessarily have to be glaringly noticeable. When it comes to growing, it's often the case where the grower thinks everything is fine because everything looks fine, not realizing that the limitations are being manifest in the form of lost potential - plants not being all they could be.
I understand that often there is a high priority placed on convenience, and that is fine; we all do things that could be done better because it's easier, myself included. Still though, it's a wiser grower who understands the potential limiting effect of certain practices when he/she weighs them against the convenience they offer.
Al, you have an interesting way of wagging your finger without point your finger. I stand corrected. Your past and recent postings on container media are what inspired me to grow hot peppers in 2.5 gallon pots. Although your methods may be regarded as more long term than I expect to keep these pepper plants going, I have already seen a marked improvement in production. Our short, cool season, with swings of as much as 40 degrees in a day are not well suited for growing peppers in the garden. Clouches are impractical because of frequent high winds exceeding 50 mph so I have toyed with different ideas to produce enough hot peppers for my needs. The goal is year around production with fewer plants to contend with.
My available potting media materials consist of the following: Wood chips, wood chip fines, composted hay/horse manure, well aged cow manure, spent vermiculture media (originally peat moss), crushed rock fines, crushed oyster shells, vermiculite and pearlite. With the exception of peat moss and the last three items mentioned, all of the other ingredients are readily available at no cost. I am somewhat reluctant Al to ask this question, but based on your comments above, what combinations of these materials would you recommend for a single mixed media for hot peppers?
I should mention that some peppers prefer a more alkaline media than others, and that is why I purchased the crushed oyster shells, which may not be the best choice of material for pH adjustment in this case. Treated dolomite with vinegar which produces calcium acetate, which is what smokemaster recommends. The reason I chose the crushed oyster shells was to increase the amount of organics in the growing media. Based on your comments Al, if I am understanding correctly, with the proper balance of constituents, a single media layer would work as well, or better, than several layers, to eliminate perched water. And in effect either top or bottom watering could be done without difficulty.
>> 3oz. solo cups (walmart) with holes drilled in the bottom, a 4" piece of three ply cotton twine for the wick,
Thnaks for both those ideas: 3 oz. Solo cups and 3-ply cotton twine. Cotton twine never seemed "fine enough" or "soft enough" or "porous enough" to be good wicks, but if it works, it sure sounds convenient. I keep loking for water-abosrbant yarn but never find anything.
Do you twist three pieces of twine together? Or are you using one length of comemrically availble twine that happens to have three plies of finer stirng inside it as purchased? I'm thinking that winding three lengths of butcher twine around each other would produce capillary channel between each lemgth of twine.
Do you tie them together in any way, like with thread, to keep them from unwinding?
>> a set of used oven racks from a second hand thrift store set over top of the bottom half of two jiffy seed starter kits as the water container
Love it! Do the racks rest right on top of the 1020 trays? That seems a lot of weight for flimsy plastic trays.
At Goodwill, roasting pans might be as cheap as platic trays, on half-price day.
P.S. I was thinking about running the wicks all the way up the side of the cells, so that water would wick UP the twine, and then, since it was in contact with soil all that length, move horizontally out into the soil. Maybe even run the wick right up the center of the cell through the space the root ball will fill.
That way, even if my soil mix was too coarse to be great at wicking UP very far, it might still be good enough to wick water sideways a shorter distance.
I'm also paranoid (or reasonably concerned) about salt buildup during bottom-watering or any uphill-wicking scheme.
I do keep a capillary mat in the bottom of each tray to facilitate "bottom-watering" without any pool of standing water that would drown roots. The mat spreads the water around to EVERY cell as long as the mat is damp. Knowing that every cell or pot has SOME water available to it helps me refrain from gross over-overwatering and hence avoiding anerobic or hypoxic soil.
However, whether the water is added from the top or from the bottom, all unconsumed salts and colloids stay inside the tray and build up, either in the soil or in the mat.
My "solution" fits well with my weakness for over-watering.
- Sometimes I top-water with considerable excess water.
- Water runs out the bottoms and into the mat.
- Turkey-baster-time, to remove salty water, though I wish I had a wet-dry shop vacuum.
- When the mat "looks dirty", I shift the insert tray or pots to a different tray with a cleaner mat.
- Take the "dirty" trays and mats outside, use a hard mist to blow particles away.
- Soak and pour off to remove most salts.
- Peroxide or bleach if it seems desirable, thoguh then I'm paranoid about rinsing that out enough.
Probably a better practice would be to flush with a controlled-pH solution, and using slightly different pH each time I flush. I'm guessing that the best practice would be to top-water every day, with moderate excess twice a week, and suck out any overflow every time, using no capilary mat or cvhnaging it out weekly or monthly.
I'm not aiming so much for optimum growth conditions, as I am trying to avoid noticeable harm caused by bad watering habits (either forgetting to water and drying out, or overwatering and drowning roots).
Maybe if I try to start Lisianthus / Eustoma / Texas Bluebell / Prairie Gentian from seed,they will be so fussy that I'll have to be more conscientious and disciplined.
It depends on how coarse these are, and what % of the mixd they are: wood chips, crushed rock fines, crushed oyster shells and Perlite.
I *THINK* that, to get the drainage benfit of coarse components, don't they have to be more than 80% or even 85% of the mix? It is so easy for fine stuff to fill all the pores and voids and defeat the coarse parts. Then even a little water fills all the rest of the voids and channels and then hey-presto, where did all the air go?
If the wood and crushed rock and shells are "fine", like, say, less than 2 mm in largest dimension, maybe all the organic matter is clogging your pores and giving you less aeration and drainage than is optimum.
Pots are just so much fussier than a multi-square-yard bed sitting on top of something that drains at all.
If you're getting pretty good results in a 2.5 gallon pot, I'm guessing that you must have quite a lot of relatively coarse wood chips: 3+ mm or 1/8" and larger. Or your crushed rock fines include some fine gravel (2-6 mm large dimension). Fine gravel (4 mm grit) is what I would wish for a lot of, inside a 1-5 gallon pot with high-organic soil.
I've been paranoid about using wood since I saw some nasty gross fungal hyphae in a wet, hypoxic clayey bed where I had added too much wood, but I doubt your pots have all the problems that bed had! Do you pre-compost your wood chips any? Say, with manure?
I always have opinions. Less often, experience.
I think we're headed off the reservation here (OT), but hopefully RC will indulge because we're still within hollering distance of the original topic. I always hope that people will look at my offerings as being firmly rooted in science or good horticultural practices and then act on them, but it often doesn't go that way - no way to plan on how receptive to information someone will or won't be. I think I try not to come off as wagging my finger as often as I can, hoping that others will look at science & reason as unemotionally as I do and look at it as my offering a hand up. That isn't to say I don't get excited about things related to growing, or helping people, or even having a spirited discussion - I do. I just think that when we get on the subject of soil science, things are more predictable and easier to nail down than many other areas associated with growing things. That's probably because the physics and chemistry that come together in forming the basis for soil science are rather well-defined at the level in which we view it as hobby growers, leaving us most often able to offer "it is" with a high degree of certainty, rather than an unformulated "it might be". In the end, it would seem unusual indeed that I would have much interest in whether or not someone takes my advice or accepts what I say as sound ... if it weren't for the fact that I get so much personal satisfaction from the fact that something I might have offered has contributed in some way to the pleasure someone else is getting from their growing experience. I try hard to help, but I'm not good yet at conclusively separating those that want it from those that don't. My best hope is that the former outnumber the later, and as well that I might include you among the later. ;-)
I don't know if the wood chips you refer to are chipped trees or possibly conifer bark, which is what I would prefer as the basis for a soil. If it was my soil, I would eliminate the straw and manure as candidates for inclusion based on the fact they break down into pore-clogging size very rapidly and will generate a lot of heat (during the composting process), so will wood chips if they are chipped trees including sapwood/heartwood. Uncomposted wood products will also immobilize N to a very notable degree, such that you'll probably need to compensate for it by adding plenty of additional N, and at some point during the composting process you should expect a very high spike in pH when/if using wood products from hardwoods.
I think you would be very happy with a soil that was made with
5 parts pine bark fines (dust - 3/8")
1 part peat or vermiculite
1 part perlite
I'm not sure if someone is recommending CaC2H3O2 as a Ca source or suggesting you combine dolomite with vinegar which > [Ca+Mg(CaC2H3O2)]. In either case, both are salts and very soluble (but decrease in solubility as temperatures rise - somewhat unusual). I might be missing something, but I cant see the advantage in adding something so soluble that will immediately increase EC/TDS of the soil solution and need regular replenishing, when dolomite has less impact on EC/TDS and probably wouldn't deplete until the end of the second year a plant was in the same soil when the Mg fraction would likely need replenishing because it's approx 125X more soluble than the Ca fraction. If a more soluble form of Ca is desired, or the goal was to supply Ca w/o impacting media pH, then CaSO4 (gypsum) would get the nod from me, which would then most likely require you to supplement Mg, with MgSO4 being the drug of choice for most. I guess what I'm saying is that soil makers use dolomitic lime for a reason - it's inexpensive and hard to improve on.
OK - I got off the track when I got to 'dolomite' in the recipe. If you can't find or don't want to use conifer bark fines, and are limited to the items on your list, I suppose I would swap the wood chips for the bark, but the ratio of ingredients I would suggest would require at least some feeling for the size of the particles making up the wood chips & fines, and the potential issues I mentioned still stand as probable things to deal with.
First, I never mind thread drift, and second, this is drifting in a very interesting direction and I'm learning things. Please carry on!
Third, I understand and mostly agree that a REALLY well-draining mix and carefully optimized, frequent watering can be slightly better for plants than using wicks or mats, but for some people and some circu,stances there is a place for "easy and good" instead of "much harder and slightly better". I admit that "easy" and "hard" are very subjective terms!
Probably different people value differently the improvement from
"good enough for my purposes and ability to discern"
"proveably better if you measure it closely enough".
I didn't know that oyster shells were any more soluble or prone to releasing ions or soluble molecules than dolomite lime. I thought both were mostly insoluble until they netralized excess acid, and then assumed both would have released similar amounts of ions.
Note: "thought" and "assumed".
- If oyster shells have much bi-carbonate as distinct from carbonate, then I do understand what you're saying.
- If Calcium Carbonate is more soluble at any pH than Calcium-Magnesium Carbonate, then I guess I understand.
- Is the pH buffer point of oyster shell higher than lime, so that the shells try to raise pH higher than lime does?
- If it is the other 5% of "stuff" in oyster shells contributing solutes, I understand.
- If it has to do with vinegar, I don't understand the reference to vinegar. Decomp products from wood chips?
I used to like the idea of coarse oyster shell because it would supply both grit and pH control in one ingredient, whereas limestone is mostly available as fine powder.
Al, you're one of the very few online people I would ever take advice from without knowing the full "why and wherefore", but why do oyster shells increase dissolved solids and/or electrical conductivity more than dolomitic lime?
Oh - I was replying to MR about Ca acetate, the product of vinegar + CaCO3. I didn't even see several of your posts until just now. I probably got called away before I finished & you posted several times before my post went up.
Oh! Maybe someone wanted to add Ca++ and soluble organics?
I've been describing myself as a pine bark fanatic on other websites, even using it for starting seeds.
Thank you for saving myself from my heavy hand with the watering bottle!
The ironic thing is that, once I got fast-draining mix PLUS the capilary mat, I started to feel better about letting several days go by between waterings. And it's been a long time since I lost seedlings to damping off, even when left too long in the tray.
So even though your ideas enabled me to get by with some bad habits, now I'm even getting over those bad habits!