because vertical farming is a hoax. best u could do is practice hydroponic farming: save about 90% of water usage. Otherwise farm footprint is farm footprint (plants need sufficient sunlight). plant LEDs consume 200w/m² for lighting, solar panel produce 200w/m² of electricity from sunshine. Leds/solar panels aren’t efficient enough to allow vertical farming, its just (un)feasible under sunlight farming with extra steps