Thatch is a dense layer of decomposing dead roots, underground stems and leaves between the visible grass blades and the soil surface. Actively growing lawns accumulate thatch as a natural occurrence. A build-up occurs when the production of this layer exceeds the ability of the soil’s organisms to break it down. When mowing at the correct height and frequency, it is not necessary to collect lawn clippings. Clippings contribute a minor amount to thatch accumulation, they decompose rapidly in contrast to the tougher roots and underground shoots. A small amount of thatch (1/2” or less) is beneficial for the lawn, it promotes turf resiliency and provides nutrients as it decomposes. However, when the thatch layer exceeds 1/2”, it becomes undesirable. This amount of thatch increases turf grass diseases and reduces the lawn’s tolerance to drought, heat and cold. Thatch build-up will minimize the movement of air, water and treatments through the turf into the soil.
Signs and Symptoms:
The thatch layer should be measured if large areas or patches in the lawn appear to be dried out after adequate watering, if scalping injury occurs at proper mowing height, or if the lawn does not respond well to treatments. The dark, spongy layer between the soil surface and green vegetation may be measured by cutting a pie-shaped wedge in the lawn. Thatch accumulation above 1/2” will present potential problems.
Cultural Practices for Control:
1. Core aeration removes plugs of thatch and soil and deposits them on the lawn surface to deteriorate. As the plugs sift down into the lawn surface, they deposit soil into the thatch. This will increase the thatch degradation as a result of the microorganism activity in the soil. The lawn will also experience other benefits of core aeration, including water and air infiltration and reduced soil compaction.
2. Topdressing the lawn manually with 1/8” of soil which matches the existing type will also deposit soil into the thatch layer. This practice may or may not be practical for the homeowner.
The Green Pointe staff is always ready to assist you with your lawn. Please call if we may provide any information to enhance your lawn’s health or appearance.
Please call our office if you have any questions or visit our “Questions” page to review other frequently asked questions and answers. (801) 261-1171