A good corn yield is 250 bushels per acre (per year). That gives 14,000 pounds of grain.
Advanced climate-controlled greenhouses, like Village Farms International, Inc., commercial GATES greenhouse, today are producing more than 850,000 lbs of vegetables per acre per year, 61 times a corn yield.
Supplementary lighting will increase that to one million pounds per acre per year.
Climate-controlled greenhouses are probably the most productive agricultural systems anywhere.
As we look to the future, a combination of produce suppliers is the most likely development, with the middle of the market supplied by large local greenhouses, the most affluent consumers paying a premium for ultra-local rooftop production, and the value-conscious customers continuing to purchase vegetables grown seasonally and shipped in from other regions.
Paul Selina, V.P. for Applied Research, Village farms International, Inc., Resource - Published by ASABE, Mar-Apr 2013, page 25