Lawn Thatch: 3 Helpful Pros and Cons

Lawn thatch consists of a layer of roots, stems, and dried grass that accumulates on your lawn’s surface. We highlighted some concerns you should have regarding thatch in our post about grass catchers. However, thatch also has a few benefits. 

Here are 3 pros and cons of lawn thatch, and how to maintain it:

Pro: Lawn Thatch Traps in Moisture

If you’re able to maintain ½ an inch of thatch, it’s very useful. A healthy layer of thatch helps trap moisture in your lawn’s roots. While this is more beneficial for warmer climates that receive less rain than in the Pacific Northwest, it becomes an asset during the summer months, when we can end up going a long time without rain. 

Con: It Can Suffocate Your Lawn

Thatch thicker than ½ an inch limits your soil’s ability to get oxygen, water, and nutrients it needs to thrive. Make sure you maintain your thatch and aerate when necessary, otherwise your root system will weaken and your grass is likely to die prematurely. 

Pro: Insulation

Lawn thatch traps in heat and prevent your roots from freezing when it gets colder. As a result, you’ll enjoy a lush, green lawn long after autumn sets in - assuming you’re using good landscaping practices. 

Con: It can Invite Diseases and Pests

In cooler, wetter climates, a thick layer of thatch can hold too much water, drowning the soil and grass. Failing to drain your lawn puts you at risk of having diseases and pests move in and infect your lawn and any number of maladies. 

Pro: Thatch Prevents Weeds From Sprouting

Maintaining ½ an inch of thatch lets your grass roots grow full and deep and helps your lawn remain lush and green. The stronger your root system is, the more difficult it becomes for weeds to take over. The weeds that make this attempt are fewer and more easily managed.

Take a little time every couple of weeks throughout the year to inspect your lawn and remove weeds when you see them. Weeding your lawn is one of landscaping's best practices, and the benefits are in perpetuity. 

Con: It Prevents Pre-Emergent Herbicides From Being Effective

Thick thatch limits pre-emergent herbicides’ ability to do their job. Pre-emergent herbicides control your lawn’s weeds as they germinate. If the chemicals can’t break through the layer of thatch and penetrate your roots, the herbicides can’t keep the weeds from sprouting. 

Maintaining Lawn Thatch

Prod around the grass until you find the brown layer near the bottom of the grass blade. With a measuring stick, poke a hole through the brown layer to the top of the soil to discover how thick your thatch is. 

If your thatch is less than ½ an inch thick, you don’t have to worry about it. If it’s greater than that, you should dethatch your lawn. We recommend dethatching when your grass is growing so it can fix damage caused to your lawn before the next dormant period. For cool-season grasses, we recommend dethatching in early spring or early autumn. 

Once you get in the habit of monitoring lawn thatch, you can enjoy the benefits without the drawbacks, and your lawn will be easier to maintain.