Proper site preparation is the most important step to a healthy lawn, according to Kansas State University. The soil must be cultivated in order to encourage roots to grow deeply, and thus efficiently absorb the needed nutrients and water. Grass with strong roots tends to be healthier because it is less susceptible to insects and disease. It also resists weed invasion. Take the time and effort to prepare the seedbed properly and you can expect rapid, uniform lawn establishment.
Fall seeding is usually recommended for grass, and all the soil preparations should be completed several weeks prior to planting. This means seedbed preparations ought to begin in mid to late summer. At minimum, allow prepared soil to settle for seven days before seeding.
Prior to planting grass, remove perennial weeds like quack grass. Either dig them out by hand or by applying herbicide. If you dig them out, be sure to remove the entire root and stem of the weeds so they do not simply grow back to compete with the grass seed. If you use herbicide, the University of Illinois recommends a translocated variety, which will move within the plant to affect the whole, providing the best control of perennial weeds.
Lawn grass tends to grow best when pH is between 6 and 7, which is slightly acidic. It also needs proper nutrition. A soil test will reveal soil pH as well as provide information about the amount of variable nutrients in the soil, nutrients such as phosphorus and potassium. Soil test results then guide how the soil should be amended.
It is easier to add the needed nutrients to soil prior to seeding grass, and it will help get the seed off to a good start. Soil pH may be lowered by adding elemental sulfur or raised by adding agricultural limestone. Soil test results will also help determine what kind and how much starter fertilizer should be used. Soil that is primarily sand or clay will benefit from the addition of compost or other organic matter.
Tilling and Leveling
Use a plow, disc, or tiller to till the soil to a depth of at least 4 to 6 inches, working in soil amendments and aerating the soil. Remove any debris or large rocks. Then allow soil to settle for a couple of days and rake by hand to break up large clods, fill in depressions and level out any raised areas. Create slopes of one to two percent grade away from any buildings on the site to ensure good surface drainage. When soil work is complete, irrigate the area and allow soil to settle.