When preparing the soil for a new lawn, particularly at a newly constructed home, remove any rocks or debris and grade the soil so it slopes from the house at a drop of 1 to 2 feet per 100 feet. This grading process ensures good drainage around the home's foundation. Till the soil to a depth of 6 inches, incorporating 2 to 3 inches of compost into the soil. The compost improves drainage, and over time, creates a loamy soil. If the topsoil is gone, haul in new loamy topsoil and add compost to it.
When filling in bare spots in the lawn, add 2 inches of compost and dig it lightly into the soil, raking until smooth. The compost will lighten the soil and add a slow-release form of nitrogen, which encourages strong, healthy grass growth.
Once the soil is prepared, spread the seed with a drop or rotary spreader, applying only the amount recommended on the package. Applying too much seed can cause a dense lawn prone to disease. To fill small, bare areas, mix the grass seed at a rate of one part seed to three parts loam soil. Spread the mixture over the bare spots. Rake to lightly cover the grass seed with soil.
Once the lawn seed is vigorously growing, top dress it annually with 1/2 inch of compost. Rake the lawn to remove thatch and leaves, and mow it to a height of 1 inch. Apply the compost in the fall or early spring, smoothing it out with a rake. The compost slowly works into the soil, improving drainage and providing nutrients.