It might bring too much water into the soil mix. I don't know for sure if it would be ok. better wait for more replies.

You can get 5" online--google "pond supplies" or "pond baskets"

Rollie,

Strongly recommend that you do not use anything larger than a 5" diameter wicking basket. I used the large 9" ones last year and the potting mix stayed way too wet. Had to retrofit to the 5" basket late in the season, and this size worked fine. Go to a Hydroponics store and ask for a 5" "NET POT".

Raybo

You don't need to purchase anything. Use a food grade container salvaged from your household recycle bin - yogurt container, juice container, etc.

Dan

Here's something that might work. What's everyone's thoughts on this?

EG

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EG,

What I have discovered (through trial and error) is that the big "brick" of wetted potting mix acts as a charge-pump to send the water to the surface above, no matter the size of the orifice. I experimented with a 1" by 8" orifice with the basket you show, and I still got too much moisture topside.

Think of a big chunk of ice in that large wicking basket, and what that would do to the temperature of the potting mix above it. I cannot explain it from a scientific basis, but my "nose" is telling me that a 5" diameter, by 4" high wicking basket is just about right for a 31 gallon 'Tainer. Another benefit you pick up is that the aeration bench is then 2" shorter, so the depth of the potting mix grows by 20% to 12". Not a bad deal!

This would make an interesting study project for some AG college students!!

Raybo

Raybo - Hmmm....you've really got me thinking, now. The reason I wanted to experiment with this, is because in my mind - it was the same thing as reducing the effective area of the wicking basket, thus making it smaller.

EG

Raybo - I've been thinking about the properties of the original wicking basket (8.75 x 8.75 x 6)versus the smaller basket you now use, and have decided that the reduction of effective surface area for the soil that is suspended in the water has been reduced by around 65%. Believe me, this is not some number that popped in my head, I had to perform alot of mathematical calculations to come to this conclusion. It's really not the size of the basket that is used, instead it is the surface area of soil, that actually comes in direct contact with the water. The original basket has roughly a surface area of 250 square inches, while the smaller basket has around 75 square inches. I figure the effective surface area of the bottom of the original basket is around 30 square inches, so I'm gonna try to duplicate the effect of the smaller basket with what you see in the photo above. I'll have to make some measurements tomorrow, to see how much of the foil needs to be removed - so it will be pretty close to yours. Ain't this experimenting fun?

EG

EG,

If it were a fast flowing orifice like a firehose, then yes, the opening does indeed act to throttle the flow. But in a slow moving capillary action movement like wicking, the orifice opening has little relationship to the wetness factor.

My thinking is that the potting mix on top of the aeration bench is attempting equalibrum with that in the basket below. The bigger the wetted mass in the basket - - the more saturated the potting mix adjacent to it, the more moisture will flow up into the mix above the aeration bench.

I would really love to have an expert in water hydrology sort this out, and come up with some kind of Quadratic Equation to make sense of it all mathmaticaly, but this is my best reasoning as of today.

Raybo

Raybo - just for experimenting purposes, I think i'll try this in at least 1 or 2 'tainers. I'll have to get a meter to monitor the moisture with. I don't know of anyone that specializes in this area, but am willing to be the guinea pig in this experiment. I'll keep you posted on the outcome. BTW, while using the large basket, did you notice any BER or other problems with your toms last year? Mainly taste....

EG

EG,

I had minor BER, but perhaps I forgot to add Dolomite Lime to those 'Tainer when planting. Here is a photo of my Moisture Meter reading - - and while these cheap devices are not at all accurate in absolute numbers, they do indicate general range information:

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Another telltale that I observed is the extreme stalk growth seen here:
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While these plants were extremely productive in terms of quantity, I do feel that they received too much moisture. I am told that you want to "stress" the plant to produce better flavor (similar to grapes), so keeping the Meter in the "Moist" range is my quest this year.

Raybo

Hmm....I haven't heard about the stress thing. One thing's for sure, those tomato plants in that picture are freaky looking! HA! But, that sure is alot of toms growing, too. Man...that's insane!

EG

Yeah, it's like I didn't want to turn my back to the plants while working in the garden - - if you know what I mean.

My second crop of 2008 (Fall) where the 'Tainers were modified to the 5" smaller basket produced more normal looking vines.

Raybo