A thin layer of sand or soil to the grass surface (top dressing) to level renovated areas or fill small depressions may be needed. In addition, proper top dressing has been documented by research to be the best overall method of controlling thatch. Top dressing provides an ideal habitat for soil microorganisms that decompose thatch naturally. Frequent, light sand or soil top dressings have been repeatedly shown to be the most effective and constant method of reducing thatch.
Top dress with soil similar to the native soil on which the grass is growing and use as little as possible to minimize layering. Never bury the grass with sand or topsoil when leveling or filling depressions, since this may kill the grass. Do not top dress centipede or St Augustine heavily or conditions favorable for disease may develop. Sterilized topsoil should be used to prevent weed seed introduction. Sand contains no weed seeds and promotes a base for turf grass to grow and aerifies the soil.