My preferred wick set-up:
{{gwi:4260}}

Your 2:1 Turface:bark will be very water-retentive, though the wick should be quite helpful. Be sure it (the wick) doesn't contact the effluent in the collection saucer - that water drips off the wick into the saucer or down the drain.

Al

Al,

Thanks so much for the photo. But I'm not sure I understand what I'm looking at, so . . .

1. Is the white plastic I see a temporary coverage cap on the drainage hole? I can't figure out why the attached black handle seems integrated with the screen. Or is the handle attached only to the screen?

2. Does the wick you have remain exactly as you show it -- to be covered by gritty mix? Or do you drop the loose end down the hole-to-be? If it stays as is, I can't envision how/why the water would flow to the knot (rather than just staying where it is along the whole cord.)

3. If my pot in not sitting in the effluent, but lifted above the saucer, is it still a problem if the wick touches the water below? I was experimenting with a wick connecting one bowl of water and a lower bowl (the wick running over the rims). The wick was sitting in the water of the higher bowl and eventually, as the water transferred, it was sitting in the water of the lower bowl, but the top bowl was soon bone dry. Or is this not really what would happen with the pot and saucer? I generally have a pretty good imagination, but I've been struggling to get my head around this.

4. I am a little anxious about my proposed mix being very water-retentive. I've read that blueberries, and bilberries in particular, don't like what you call "wet feet." Maybe my fig wouldn't be happy either. What if I managed to use just a little bit of the #5 gravel I have access to? Would something like 1.5 Turface, 0.5 gravel, 1.0 bark plus the wick be a better way to go -- or an inadequate fix?

Thanks for your patience. I usually follow directions a lot better than this. :(

Claire

You're looking down at a high-fired, unglazed bonsai training pot. The mesh material is plastic canvas. It comes in 9 x 12 sheets and is used for needlepoint projects, available from hobby stores. The 'handle' is a piece of wire (like a pin-stitch staple) that secures the drainage material in place. You could simply use a larger piece of insect screening and let the weight of the soil hold it in place.

The wick stays just as it is and is covered by soil. There is already a 2-3" 'tail' hanging below the mesh - you just can't see it. The knot is loosely tied and just holds the wick in place. It's really not needed.

It IS an issue if your wick dangles in the effluent. There is a process called 'isotonicity' during which the level of salt in the effluent will try to equalize (reach a state of isotonicity) with the soil solution. You want the salts in the saucer, not back in the soil, so allowing the wick to contact the effluent is counterproductive to that end.

In your experiment, were you using soil in the upper container? Imagine this: You saturate unscreened Turface with distilled water and let it drain into a saucer, using a wick. Stir a teaspoon of salt into the collection saucer of distilled water and allow the wick to dangle in the saltwater. Before long, the concentration of salt in the saucer and in the soil solution will reach an equilibrium (isotonicity).

I have to be honest. The reason the gritty mix works so well is because it holds good amounts of water w/o holding perched water, and because it is highly aerated. Mixing large gravel with Turface doesn't impact the ht of the PWT, drainage characteristics, or aeration. It does, though, reduce the total volume of water the soil is capable of holding, which is a plus.

Al

Al,

I'm grateful for all your clear and detailed explanations. Most especially, I needed to hear this:

"Mixing large gravel with Turface doesn't impact the ht of the PWT, drainage characteristics, or aeration. It does, though, reduce the total volume of water the soil is capable of holding, which is a plus."

With all that I've been reading on this site, I should have understood this, but somehow I completely missed the concept. I thought that if drainage was good, and there was no PWT, then there was no problem with any amount of water held inside the clay or other elements. Now it's dawning on me that the water in the clay is also "water retention" and possibly, in excess, as bad for the plant as the PWT. Have I got that right?

Well, it late and I'm really tired, so not quite ready to face the idea of working with two 80 lb. bags of gravel -- but maybe in the morning I will be less faint of heart.

I'm thinking it must be hard for you -- having discovered what you know to be the perfect, all plant soil -- to have some newbie continually trying to make adjustments to it. Please understand that this is mostly fear -- fear about not being physically able to work with the gravel, or with the pots once they are heavy with gravel -- fear of my balcony collapsing under the weight, etc., etc. But I tend to over-think things . . .

Thanks again.

Claire

Claire - I understand where you're coming from. If you lived closer, we'd solve the dust and weight issue by having a little screening party at my house, so you wouldn't need to worry about the dust, & so someone could carry the materials to somewhere convenient for you. ;o)

Don't forget, I'm not selling a soil, only a concept. I DO think it's hard to improve on the gritty mix as an all-purpose soil. I mean ..... it's adjustable for water retention, holds good amounts of water and nutrients, is durable, almost impossible to over-water when using it, roots love it ...... what's not to like? I DO understand that it's a little heavier than other soils, and some need to work around that issue. Others have made a fuss about how quickly it drains, but jeez - fast drainage goes along with a higher degree of aeration goes along with better root health goes along with happier plants goes along with a more satisfying growing experience.

I guess I always have plenty of patience with people (like you) who are trying to employ the concept within their limitations, but I tend to lose patience when people start changing things on a whim, because they 'think' something might work better. This often occurs before they've even given the soil a try, or even fully understand the whole aeration/PWT/drainage concept. I don't mean I get upset, it's just that I realize I'm banging my head against a wall and it feels better when I quit. ;o)

"Now it's dawning on me that the water in the clay is also "water retention" and possibly, in excess, as bad for the plant as the PWT. Have I got that right?"

Not quite right yet. Plants don't 'drink' water, they absorb it a molecule at a time - in the form of vapor and from the thin film on colloidal surfaces in the soil. Water held in internal pores of particles like bark and Turface provide a healthy reservoir of moisture the plant can use. When soil particles are uniform and large enough that the soil holds little or no water in a PWT, the rhizosphere (roots and soil) is a happy place. Root function and metabolism proceeds at a sharp pace, within other limiting factors. When we fill part of the rhizosphere with water, root function and metabolism suffers, we experience a cyclic death and regeneration of fine roots, and we significantly increase the likelihood of root rot becoming an issue. This excess water also makes it difficult to water to our plants' best advantage and to control accumulation of soluble salts.

If it was a perfect world, Turface MVP would be a little larger in particle size. Screened Turface, by itself, holds not only a lot of water, but it holds a PWT as well. Unscreened Turface holds significantly more water because of the much taller PWT (in comparison to screened MVP). This makes the PRIMARY issue the PWT.

Turface gives up its moisture quickly, by diffusion when particles in the soil are large enough. The gritty mix never becomes hydrophobic (water-repellent) because the Turface always readily absorbs water. Even if the bark has become very dry and hydrophobic, wetting the Turface allows water to diffuse into the bark within a short period. If, however, you are growing in 100% unscreened Turface, the Turface becomes saturated quickly, but with gas exchange limited by particle size, air is slow to return to the soil, which is not a good thing.

Perhaps you could do some research here about the larger DE available. We started out using a product from NAPA (#8822), but someone discovered that a CarQuest product was larger and more uniform. Calcined DE is lighter than Turface, too. You may find this is where your search for something that will give you the aeration/drainage you're looking for would be most productive. Try this thread for more info, Claire.

Take care.

Al

Al,

I can't say I would like to live closer to you, as that would mean leaving southern California :) -- but I do wish you were closer to me, so I could take you out to a thank you dinner. I really do appreciate your support.

The thread you linked me to was very interesting, and the CarQuest product may turn out to be better for my situation than the Turface. I have written to two of the posters who had just bought the CarQuest to see how it's working out for them, and on Monday, I will call a CarQuest branch that is a couple of towns away from me.

I was surprised that no one on that thread picked up on one poster's mention of MuleMix. That product is not available to me (only in the eastern half of the country), but it is advertised as conditioning clay for athletic turf and it comes *sized*! Seeing that made me google for a sized product in my area, and I came up with DiamondPro -- which I'll also check out on Monday.

Meanwhile, I think I'm clear now on the water retention issue. (It was helpful to have PRIMARY capitalized -- which really made it poke through my gray matter.) I hadn't realized that even screened Turface would contribute to PWT, although not as much as unscreened.

And learning that, I thought I'd try an experiment to see what happens if I up the ante on wicking. If I can find a fix for using Turface -- which is the proven product so far -- that will be best. I have three bags of it now sitting on my balcony!

Here's what I did last night: I took the tiny plastic cup my spider plant came in (the cat's food), and cleaned it out. Then I cut a long rectangle of thick viscose ( http://www.shammysolutions.com/site/1618064/page/847748 ) about 3" wide and placed it inside my "pot": down along one side, across the bottom (where it covered the bottom completely) and up the other side.

Then I filled it with 2:1 unscreened Turface, screened bark. (I also stuck the tiny spider plant back in but those roots are so shallow, it probably makes no difference to have it there.) I ran water through until it was streaming out the bottom. When I stopped running the water, the stopping of the water was rather quick and final -- but the material had puffed out a little through the drainage holes and I thought they might continue to act as wicks.
This morning, the upper section of the mix was definitely dry and the lower section (I was able to poke my finger down to the bottom) was moist (wet). So, we'll see what happens by tonight.

Even if the mix is completely dry by tonight, I know there might be other reasons why this won't work long term. Here are some thoughts about possible problems:

1) The viscose will hold water for quite a long time. Ideally, it will release it when needed by the plant, but maybe not. Maybe the wetness would hurt the roots that touch it. And maybe the roots could actually grow into the fabric.

2) The viscose is a form of rayon, which is synthetic and very hardy. (Also "breathable.") But I would be using this on my fig tree container, and who knows if it would last 2-3 years between repotting.

Thanks for lasting through such a long post. :)

Claire

It sounds like you're using the wick incorrectly. You want to remove excess water from the pot, not retain it. Remember - soils that require frequent watering are generally going to be much better for root health than soils that can go 4 or more days between waterings.

You need to have a portion of the wick hanging down from the pot to 'fool' the water into 'thinking' the pot is deeper. To illustrate: poke a small hole in the rayon you have covering the drain. Completely saturate the soil and wait for it to stop draining. Now, stick a toothpick far enough into the soil so it stays in place, and notice how much MORE water drains from the pot.

If your soil is very heavy, it might be important for the wick to function indefinitely; but if the soil is only moderately heavy, you might not need the wick beyond the length of time it takes for the plant to colonize the entire soil mass with roots. The reason we employ the wick is to get air back into the ENTIRE soil mass as quickly as possible.

People who grow in heavy soils often claim their plants are as healthy as can be, but we know that is not true. Roots that are subject to anaerobic conditions die quickly - in a matter of hours, in some cases. So, if there is a layer of soil that remains saturated for days, we can be sure there are roots that are dying. When the plant uses the water from the bottom of the pot, roots can start to regenerate again, until the next time the planting is watered. This cyclic death and regeneration of roots is an expensive energy outlay for the plant, so you can see you're striving for 'damp/moist' - not 'wet' or 'soggy'. This is where the grower convenience vs plant health comes into play. It's 'convenient' to use a soil that needs infrequent watering, but it comes at the price of a reduced potential for best growth and vitality. To be fair, the opposite is also true. The price for a highly aerated soil that drains well and produces happier plants is more frequent watering and the fact that you often have to make the soil yourself.

Al

Al,

I did run your experiment, first on my existing pot where I didn't water again, and then on a newly prepared pot where I followed your directions exactly.

I didn't want to water my existing pot because in the 2-3 hours since I wrote, the soil is even drier than it was this morning. So dry it's not even sticking to the viscose. Definitely not wet or soggy. So I want to wait and see what it's like by nightfall (a full 24 hours after watering).

I used a very large (upholstery) needle (I have no toothpicks) , and no water at all came out. However, I don't feel this is a decisive result, as it is a very dry day today.

Next I prepared a new pot, ran the water through for a while and then waited for 20 minutes for any additional water to seep out through the viscose "puffs" which are slightly lower than the base of the pot (are these not wicks, short as they are?) Once again, I used the needle to poke a hole in the fabric, pushing it almost to the top of the soil. I was applying downward pressure on soil which squeezed the viscose and made some additional water come out of the viscose in a couple of other holes (there are a dozen holes in this tiny pot!, but nothing, no water at all, drained from the needle. So I think there is no PWT in the soil, only in the viscose.

I think this material is very, very different from other kinds of rayon. I can dry sweaters by lying them flat on this material -- something impossible to do with any other material. And if you lay a thick piece of viscose on your kitchen counter and completely saturate it with water, you can pick up material and find no water underneath. It also dries pretty fast.

I'm not saying this is going to work -- it does sometimes rain here. And there are the other possible problems I mentioned before, but I do think a PWT in this set-up would have a hard time holding its own.

Claire

For those who have been following this thread and want to know more about substitutes for Turface which could work without screening. . .

1) CarQuest has both fine and coarse DE. The course is their number #8033 and is sized at 1/4". At about $7 per 25 lb bag, it's pretty much the same as the $14 Turface for 50#-- unless you're sifting Turface and have to figure in that loss. I have had one "good" report on the product, but the person has only been using it for about 5 months.

2) If you prefer calcined clay (which is what Turface is) instead of DE, and you're in the eastern half of the U.S, you can check out Mulemix.com for a sized version.

3) For calcined clay all though the US, there are Diamond Professional dealers (the Find A Distributor search seems to cover every state) http://www.diamondpro.com This product has "no dust" and " a more consistent, uniformed particle size to improve drainage. " The guy at Crop Production Specialists tells me it's definitely not smaller than 1/8" (They do have "Top Dressing" at more like a 1/4" but it's not sorted and it is dusty.) The Pro is about $11 for a 50 lb. bag.

I'm returning the two unopened bags of Turface I have. (Even without screening, and wearing a mask, the dust under water pressure was too much for me and I had a bad reaction.) Instead I will be buying the Diamond Pro.

Even with the Diamond Pro, I will have to use the rayon "lining" for my pots. (Without gravel, there would still be some PWT). I just don't know yet how much lining I'll need. Yesterday's experiment with the Turface, using a 3-gallon pot, and lining for about half the pot, created a need for watering after 24 hours. My guess is that the consistent sized Diamond Pro will require less lining, but I'll have to do more experimenting.

Claire

If the Diamond Pro is larger than the Turface, it will most likely require even more frequent watering.

I'm having a hard time envisioning this rayon lining experiment.
I have containers that are much smaller than 3 gallons, and they don't dry out within 24 hours.


Josh

Josh,

"If the Diamond Pro is larger than the Turface, it will most likely require even more frequent watering."

Well, at about 1/8" (by report), I'm not sure the bits are much larger than the Turface, but supposedly there's no dust and, because they are sized, little or no fines. So, that's why I said I'd probably have to reduce the amount of lining for the Diamond Pro.

"I'm having a hard time envisioning this rayon lining experiment."

I found some directions for uploading photos and I hope to have time, maybe this weekend, to figure out how to upload the lining setup for the 3-gallon.

"I have containers that are much smaller than 3 gallons, and they don't dry out within 24 hours."

Ah, so a smaller container will dry out faster! I thought that would be true, but wasn't sure since I went from very little lining on my tiny pot to lots of lining on the 3 gallon. I will have to guestimate the amount of lining for my 17 gallon pot.

I'm not sure why you make the statement about your containers not drying out. Why would they, without the thick viscose lining that draws out all the water? Right now, I can still get water if I squeeze the lining which appears below the pot. But the soil just above this lining is barely moist and the soil in the bulk of the pot (where the early roots will form) seems in need of more water.

Or so it seems to me. I really have no experience to be sure about anything I am doing or feeling here!

I won't actually get to see the Diamond Pro product until after Thanksgiving, and I'll need time to experiment after that, but I'll post as soon as I can if there are any new developments -- pro or con my theories/hopes about all this.

Claire

Claire,

I had a little trouble envisioning the experiment, too. But I don't think you're going to need any wick for any of your gritty mix containers. It's looking like you're attempting to build a proper gritty mix (which mostly means the components are correctly sized). A wick is unnecessary IMO as there won't be much of a PWT to begin with and although we say the mix holds a decent amount of water, it's not like it holds a lot (relatively speaking) in the macro-pores. Therefore a wick traveling around the container edges, or even upward into the soil, might expel the small amount of macro-pore water it touches (not good).

Chris

Chris,

Yes, I do think it's a possibility the rayon could take out too much moisture. I might even need to add a pine needle mulch then to keep soil moist enough.

I am trying to make the rayon work, though, because without the crushed gravel (which I can't manage) it's not really a "proper gritty mix" and I worry about having PWT in the pots and losing my plants.

I want to do as much testing as I can before my plants are in. But I'm guessing that however much I experiment, the roots themselves will have an impact on the way it all works -- or doesn't work.

Claire