What is thatch?
Thatch is the layer of living and dead stems,roots,stolons,and rhizomes between the green blades of grass and the soil surface. A thin layer of thatch (less than 1/2 inch thick) can be beneficial to the lawn because it helps to limit weed germination, reduce water evaporation, and protect from frost damage. However, thick layers (1/2 Inch or more) can prevent water,air,and nutrients from penetrating the soil, causing reduced root growth and increased potential for drought stress. Thatch also favors fungal growth and can harbor insect pests. The best time to de-thatching is early spring or early fall.