Local food with a capital L: New York-based Brightfarms builds greenhouses on top of grocery stores and warehouses. So if the cucumber section is running low, just run upstairs and you're good.
The system is designed to save the grocer money - if the veggies are on your roof, shipping costs go down, and the food is fresher, with a longer shelf life, meaning storage costs go down too.
Does it work? Several stores in New York and New Jersey are set to find out. If it works, maybe Brian Wilson can put a greenhouse in above his band when they perform the song "Vegetables" from Smile: