Every lawn has some thatch. It is when a lawn has too much thatch that problems occur. Thatch is the layer of living and dead organic material that lies on top of the soil. It is made up of surface roots, stems and crowns of grass plants. Studies have shown that grass clippings left on the lawn do not increase thatch. When thatch accumulates to over 1/2″, it often becomes a home to various types of insects and fungus spores that can damage or kill your lawn. Thatch also prevents water, fertilizer and air from reaching the soil and grass roots. This can cause the death of grass plants and serious thinning of the lawn.
Solving thatch problems. The best cure for thatch is to prevent buildup in the first place. The best way to do this is through regular aeration of the lawn. Aeration breaks up the thatch layer and mixes soil with it to speed up natural decomposition. Annual aeration helps keep thatch within acceptable limits.
If a lawn is seriously damaged or has a thick layer of thatch, the best remedy is usually to slice-seed the lawn, which cuts open the thatch, mixes soil with it and plants seed directly into the soil beneath it. Another solution is dethatching with a power dethatcher, which uses angled blades to pull the thatch up. After dethatching, the loosened thatch needs to be raked or vacuumed and removed.
Thatch can cause serious problems if allowed to accumulate too long. Regular, professional thatch management is strongly recommended.