Hi Kim,

The answer depends on the shape of the 0.5 acres of land. There are 43,560 square feet in an acre so 0.5 acres is $\frac{43560}{2} = 21780$ square feet. If your squares are 20 feet by 20 feet then each is $20 \times 20 = 400$ square feet and $\frac{21780}{400} = 54.45$ so you can have at most 54 squares but the exact number depends on the shape of the 0.5 acre plot.

Penny