The best wicking material
I'm in the process of preparing a 5-gallon double bucket to make a modified grow-box as a test of the modification. I'll plant lettuce in it and something else after the lettuce is harvested.
There's a wick chamber at the bottom of the inner bucket that extends down into the water chamber below, and I'm thinking about the best wicking material to use. Instructions imply that one's pot soil in the wick chamber will wick the water sufficiently, but I want to be SURE that the soil chamber really can receive water from below through the wicking material. Once put together with soil and the water, the double buckets weigh a ton and can't be "fixed" without removing everything if I should use something that doesn't sufficiently wick the water.
So does anyone have some suggestions for a tried and true wicking material in addition to the plant soil itself? I've seen the "thirsty" paper towels recommended and am wondering about putting vermiculite or even those water gels in the wicking chamber with the soil on top of them. Does anybody know about water flow rates through wick materials?