Clay soil can be a challenge for installing or growing a lawn. The soil is composed of tiny particles that are closely packed together. As a result, the soil is sticky and will not drain well when it is wet, and it dries to a rock-hard crust during drought conditions. When considering a lawn for clay soil, you should expect to amend the soil heavily to improve the growing conditions for your lawn.
Take a soil sample from your soil by digging a 6-inch hole in the lawn. Slice out a 1-inch-thick slab of soil from the side of the hole. Place this sample in a brown paper bag. Repeat this process up to six more times in your lawn. Mix the soil together and take the bag to your county extension service for soil testing. The results of this soil test will tell you what soil amendments you should purchase and the quantities of the amendments you should use to improve your clay soil.
Break up your soil with a rototiller in fall to prepare for laying a sod lawn in spring. Clay soil that is broken up in fall will be lighter and fluffier in spring. Cover the soil with a layer of straw to prevent erosion.
Break up your soil again in spring to a depth of 6 inches. Mix the straw into the soil as you break it up to improve aeration and organic content in your soil. Spread soil amendments indicated by the test over the soil to a depth of 4 inches. Common amendments for soil include organic materials such as finished compost, well-rotted manure and peat moss. Additional amendments include lime to lower the pH of soil and gypsum to break up clay soil.
Mix your amendments into the soil by passing a rototiller over the soil again. Smooth out your soil with a rake and regrade the soil so that it gently slopes away from your home.
Select sod adapted to your climate. In northern climates, choose cold-season sod such as ryegrass or bluegrass. In southern climates, choose warm-season sod such as zoysia, St. Augustine or Bermuda grass.
Lay sod in staggered rows over your lawn, starting with a straight edge such as a sidewalk. Roll over the sod with a sod roller when you have finished to force the grass roots into contact with the soil.
Water up to four times daily with up to ½ inch of water each time. Use a rain gauge to measure water from the sprinkler. Continue to water this way for up to two weeks while grass roots become established; then taper off the water until you are using 1 inch of water every 10 days.