Totally agree with Barrin92; the dollars don't stack up.
Ballpark estimate here, I've tried this with several crops and its similar
Hard comparing field farming and tower-farming but here in NZ good level farmland is ~NZ$40000 Hectare Ha (2.47 acres), most farms >300 Ha. Equipment, fences and buildings are NZ$2M+, so that makes it nearly $47k Ha, round up to $50k Ha to be safer. So you could say their infrastructure cost is $10000/Ha.<p>But farms don't have to purchase light! Lighting costs for farming $0, for 100% artificial light NZ$1.90 per harvested Kg.<p>Current production costs for e.g. wheat $2500 Ha (seed, tillage, weed-control, harvest). Wheat NZ has world record of ~17t Ha, but all of this is a lot easier (cheaper) when you can move large machines freely. Wind is also an advantage in strengthening plant stems.<p>A farming tower needs greater strength than a residential building as there are live loads like harvesting equipment and a lot of 'soil' media and/or water if fully hydroponic. So I'll use costs for a concrete multilevel parking building which is going to be at least $2200 m² (plus lighting, HVAC and fitout - not in calc).<p>So, say your tower floorplate is 1000m², and taller than residential for extra HVAC and machine space. Assume you buy farmland at $45k Ha and build 10 floors (1000m²/floor), and prob. end with ~700m² growing space per floor, means you need another three floors to get you up to a 1 Ha growing area,<p>: so 13 1000m² floors at $2200m² = $28.6M / $50k = 570 times.<p>Plus lighting at $1.90 per kg of harvestable product - which for wheat at 17t/Ha would be $32000 per crop cycle.