One of the best ways to figure out how much grass seed you need is by measuring the square footage of your lawn. As a general rule of thumb, you’ll need between 1 and 10 pounds of seed for every 1,000 sq.ft. of space. However, this varies greatly depending on the grass type you choose. For example, you will need 2 to 3 pounds of Kentucky Bluegrass per 1,000 sq. ft. but between 8 and 10 to plant Tall Fescue on 1,000 sq. ft. of land.