A small backyard can produce a meaningful amount of food, even when it looks more like a postage stamp than a farm. The trick comes down to choosing productive crops, using vertical space, and giving prime growing areas to plants that actually earn their keep.
That last part matters more than garden size. A sprawling pumpkin plant can gobble up precious ground space while producing a handful of fruit, whereas a compact planting of lettuce, herbs, radishes, green onions, or bush beans can keep the kitchen supplied much more efficiently. A small garden does not need to imitate a giant garden, and trying to squeeze everything into it usually creates more frustration than food.