How Much Topsoil is Needed for a Lawn?

Minimum Depth

• A lawn needs a bare minimum of 3 inches of topsoil, according to experts at the Ohio State University. Dr. Leonard Perry of the University of Vermont recommends using at least 6 inches to be sure of a strong root system. Shallow topsoil results in poor water movement.

The Ideal

• In order to maximize the water retention capabilities of your topsoil, maintain a depth of 8 inches recommends Dr. Rachel Poulter of the Department of Employment, Economic Development and Innovation in Queensland, Australia. She also claims that an increase to 12 inches saves even more water.

Types

• Use loam or sandy loam for your topsoil. Do not purchase any other type for a lawn. The topsoil does not need to be black in color.

Considerations

• Make sure that the topsoil that you purchase is free of Johnsongrass and quackgrass rhizomes. These weeds cannot be removed from your lawn without destroying the lawn itself.