Comment by jillesvangurp

The challenge is finding something that is energy dense, that grows quickly, and has a high value to justify the length of trouble you have to go through. Things like potatoes, grains, rice, etc. Are relatively low value and they don't grow that quick.

Potatoes especially don't like to be submerged. But otherwise they are not that hard to grow. A simple grow bag will do. That's true for a lot of root vegetables and tubers. For vegetables like that, greenhouses are more common.

With rice and grains, they grow well enough in hydroponics but you just need an enormous amount of area to get to interesting amounts. Also the growing season for that is quite long. Hydroponics favor things that you can harvest in weeks rather than say 2-3 times per year.