Hard clay soil lacks some of the nutrients that many grasses require and can be too hard for young turf roots to penetrate. When preparing to sod a yard, it is essential to properly prepare the soil to ensure the lawn will flourish.
Use the soil test kit to determine what nutrients might be missing from the soil. The most reliable kit can be ordered through the county agricultural services office. If the soil tests acidic, then add some lime to the soil by tilling. For additional missing nutrients and for the proper amount of lime to add, always consult the agricultural services office, as they have instructions specific to your growing area.
Remove any existing grass, weeds, rocks and debris from the yard. Glyphosate herbicides are safe to use for preparing the yard.
Till the entire yard site to soften the soil. Tilling should be done to at least 4 inches in depth. Observe the general tilt of the yard while tilling, and add a slight slope where necessary to drain extra water away from the yard. Add mulch at the rate of one cubic yard per 100 square feet and gypsum at the rate of 50 pounds per 100 square feet and till these nutrients into the soil. This mixture will help the soil to provide for adequate water drainage and nutrient retention.
Roll the soil to remove all air pockets and level the future lawn area. The final height should be just 1/2 inch below all patios, so that the sod will line up perfectly for mowing.
Deep water the entire yard the night before the sod is scheduled to arrive, to ensure the ground is soft for the new roots to grow into. The soil should be damp to a depth of at least two inches.