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Spring to Manage It and How Staff Report
T
here are a host of issues that challenge the landscape contractor and maintenance professional when it comes to healthy turf grass. One of most common is thatch. Every lawn
has thatch, but the health of the lawn can be either benefit or suf fer from thatch, based on a 1/4-inch of dif ference.
What is thatch? How does it impact turf
grass, and when it is out of balance, what are the effects and how can landscape contrac- tors control or improve it? Thatch is a layer of living and dead or-
ganic matter that resides between the turf grass green matter and the soil surface. The primary component of thatch is turfgrass stems and roots. It accumulates as these plant parts buildup faster than they break down.
Excessive Verses Moderate Thatch Excessive thatch (more than 1/2 inch
thick) impedes proper turfgrass root growth, while also creating a favorable environment for pests and disease. How-
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ever, moderate thatch levels (1/2 inches or less) are beneficial. Thatch acts as a mulch layer that shades the surface to reduce high summer soil temperature and evapora- tion, and competes with annual weeds such as crabgrass. It supplies food sources and a habitat for
beneficial microbes. Also, earthworms use thatch's organic matter as a way to burrow into the soil, which aids in reducing soil com- paction. It also acts as a living filter to reduce groundwater contamination, while also pro- viding a cushion that reduces turf injury.
Why Excessive Thatch is Bad Excessive Thatch soaks up water so it cannot reach the soil. As a consequence,
Above: Over-watering is one of the contributing factors that can lead to excessive thatch. It makes the lawn grow too fast, which can lead to the excessive buildup of the dead material that makes up thatch. Reducing over-watering and fertilizer use are the two things to look at to discourage the formation of excessive thatch.