These folks: http://growbiointensive.org/grow_main.html have a system that produces a complete diet in 5000 ft² (465m²) per person. It also produces its own compost, so that the farm increases soil volume and fertility year-on-year too.

(Their server seems to be slow tonight, check out this for a summary of their system: https://web.archive.org/web/20210411002519/http://growbioint... )