We recommend that you start preparing the soil at least two days in advance. Be sure to water thoroughly the night before the installation to allow the water time to absorb into the soil. Till the existing soil to a minimum depth of at least 2 inches before adding any topsoil or soil amendments. Add topsoil, if necessary, to achieve a total topsoil depth of 4-6 inches. Lightly tamp or roll the topsoil to settle the surface and create an ideal surface for installing the sod.