I like the idea of this, but I bought the shorter cones, thinking they would be adequate for my needs. Unfortunately, the cone-holders are only one size (height), and are made for the deeper cones. In order to water from the bottom, one would need to add several gallons of water to the tray, to reach the bottom of the cones. Besides the weight, I think having that much water always present may lead to mold problems. Watering from the top always has problems of mold, root growth, etc. How have other people dealt with this?
I haven't figured out a way to deal with this yet-- I tried putting rigid foam in the bottom of the tray to take up some of the volume of the water-- but of course, it floats and just pushes the cones up. I could use construction adhesive to attach the foam to the bottom, but I think there would be problems with that-- the tray has ridges so there would always be a film of water underneath and I think that will mold, too.