it kinda dosent matter if its hydroponic or soil they still need the same amount of light, and that depends on the crop, but basically there isnt a crop that could feed you if u only have a normal sized flat, even if u stack micro greens to the top and sleep in the bathtub
Was thinking of those small footprint plant towers that were circulating online a decade or so ago. Look like big upright pipes with holes in the sides for plants. Continually circulating water inside. I’m sure they’re expensive now but I bet we could throw one together without too much effort if we had the knowledge.