A lot can be grown in small spaces. There are some books devoted to gardening in small space. Postage Stamp Gardening is one of them and has lots of useful informaton.
It’s possible for a person to grow all their (approximately 322 Lbs.)vegetarian food in 200 sq. ft growing area with a 6 month growing period.
Plant that same area with winter wheat and/or winter rye, and you will have enough to make a loaf of bread every week and a half.
Increase that area to 300 sq. ft. and you’ll be able to have a loaf of bread every week, and about 160 lbs of extra produce to share with a neighbor, or sell at the farmers market.