Problems with soil are the biggest reason lawns do not grow thick and strong. Hard, compacted soil prevents grass roots from developing and water and fertilizers from penetrating the soil profile. Improper soil pH values and soils lacking the proper growing conditions including organic matter makes growing grass difficult. If we spent as much time on the soil in our lawn that we do when we plant tomatoes we would have a great lawn. The problem is the lawn is generally a large area. This makes it difficult to work the soil without the proper machinery and expensive if you need to work in many loads of new topsoil to create ideal growing conditions.
Unless some of these steps are taken to improve the growing conditions, you will continue to have trouble growing grass effectively. Clay soil types need to have organic matter mixed into the top six inches of soil. Otherwise, heavy aeration and the application of Love Your Soil can help to start improving conditions. You may need to do this several times each spring and fall for several years to break up clay soils. When renovating your lawn, correct any drainage problems before final soil grading and seeding.