Common Questions on Lawn Thatch
Thatching is one of the most important things a landscaper or homeowner can do in spring to help their lawn recover from winter. When thatch is allowed to build up, it can cause many problems when trying to grow healthy grass. By definition, thatch is a layer of mainly dead turfgrass that lies between the grass and root system below. A thin layer of thatch is less problematic because it provides insulation against temperature extremes and changes in soil moisture. A layer of thatch that is more than one inch thick can start to cause problems, that’s why dethatching is so important. Valley Green is a top supplier of cool-season grass seed so we frequently answer questions on lawn thatch.
What is the makeup of lawn thatch and why is it a problem?
Lawn thatch consists of stems, rhizomes, roots, and other organic material that has not decomposed yet. Thatch becomes a problem when turf produces more organic debris faster than it can break it down. When thatch becomes too thick, it blocks air, water, and nutrients from reaching the turf’s root system. Without access to these three things, grass will not be able to sustain itself. A thick layer of thatch also increases the likelihood of insect infestations and diseases infecting your lawn.
What is the impact on my lawn from a thick layer of thatch?
There have been cases where thatch has been so thick that the homeowner or landscaper was unable to properly mow the lawn. Areas that have thick patches of thatch develop a spongy consistency and when you mow over these, the wheels sink, and this may cause you to scalp the lawn. Some types of grasses are more affected by thatch than others. These include cool-season grasses such as Kentucky Bluegrass and Creeping Fescue. If your lawn is comprised of these grass types, it is a good idea to dethatch on a regular basis.
When to dethatch a lawn.
You’ll want to be sure to check the thickness of the thatch layer before starting the process of dethatching. To do this, you can use a garden trowel or spade and dig up a small sample of grass and soil. You should be able to see and measure the thatch layer and if it is more than one inch, your thatch layer is too thick. Other signs that a lawn may need dethatching are poor grass color and weak growth. Dethatching in spring is good timing because it coincides with the growth of cool-season grasses that flourish at this time of year. Never dethatch a lawn when it is in a dormant stage or stressed. Dethatching it may damage it beyond repair.
What causes thatch on lawns?
Thatch accumulates when the production of dead organic matter surpasses the ability of microorganisms to break down matter in the soil. Lawns that lack beneficial microbial activity often accrue thatch. Low microbial activity is often caused by the over-application of fast-release nitrogen. Thatch buildup can also occur when there is poor aeration in the soil as well as poor drainage. Watering a lawn too much also contributes to excessive thatch buildup.