I have to be the last person on my block to have an upside down tomato planter, but I'd been wanting to make one for quite some time, and although this one is not hydroponic, it certainly fits the theme of "Ann's Air Gardens."
You may remember this plant when I put it in a milk carton here.
The roots and soil are held in place with a chunk of the same open-cell air-conditioner foam that I use as plugs in the AeroGarden's grow baskets. The foam also helps keep soil from falling out through the opening when the plant is watered.
I'm hanging it indoors in the shade until I get a fabric cover sewn. I'm still thinking about the design, as I'd like the cover to come off easily for inspection, but also to protect the dirt from drying out and/or getting direct light.
My theory is that the roots, which may have already adapted to water since this cutting was rooted in water and spent the first month of its life in liquid nutrient solution, will adapt to potting soil if I harden the plant off properly before abandoning it to the desert heat. But I should note that the soil that I am using (Scotts MicracleGro Moisture Control) contains coco-noir, so that should help.
I'll add a picture when I get the cover made, and hopefully again when tomatoes appear. There are buds on the plant now, but the shock of being converted might cause them to drop off.