I moved into a new subdivision where the yards were, of course, very hard clay (no top soil remained after the construction). I brought in top soil when I installed my sod lawn, which now looks great. A neighbor said that someone told him it was not necessary to put down top soil; that the sod can be placed right on top of the clay. Is that correct?
The overall health of your lawn is a direct result of proper soil preparation prior to the installation of the sod. The effort you put forth now determines the quality of your lawn for years to come. It also makes a difference in the routine maintenance that you will have in the future. It is very difficult to improve the soil at the root level once the lawn has been established. Sod that is laid over a thin layer of topsoil or compacted subsoil produces disappointing results due to poor rooting and development. It is a good idea to have a soil test done by your county MSU Extension to determine the pH and amendments that are needed. The following steps are recommended for sod installation:
- The existing soil should be tilled thoroughly.
- Add organic material if the soil is very heavy or sandy.
- Topsoil that has been added should be well mixed with the subsoil to a depth of about 6 inches.
- Apply recommended soil amendments and fertilizers at this time. In general, a pre-plant fertilizer can be spread over the entire area at a rate of 1 pound per 100 square feet.
- Rake the area smooth, filling in the low spots and removing larger clumps.
- A finish grade should be made using a steel garden rake, making sure that there is a way for water to run off away from the house.
- After laying the sod, roll it with a water roller to remove air pockets.
- Water, water, water. The sod should be kept constantly moist and should be watered 2 or 3 times a day for 10 days with heavy foot traffic avoided for the first two weeks. And then, let the mowing begin!