Square foot gardening

https://www.bhg.com/gardening/how-to-garden/square-foot-gardening/

When it comes to planting, the formula is simple: one extra-large plant per 1x1-foot square; four large plants per square; nine medium plants per square; and 16 small plants per square.

Here’s an idea of what you can fit in each square: 

one vine tomato, pepper plant, or eggplant; 

four bush tomatoes, heads of cabbage, or heads of lettuce; 

nine onions or beets; or 16 radishes. 

Zucchini needs nine of the 16 squares for just one specimen, but you can plant other vegetables in the remaining seven squares. 

Vegetables or fruits that spread (such as watermelons) require a separate bed.