What is Thatch in Your Lawn?

worker raking up thatch from a yard

You’ve probably heard about thatch and how it’s bad for your lawn, but that’s not entirely true. A little thatch won’t hurt anybody, but how much is too much? Well, if your lawn feels squishy and spongy to walk on, then you might have a thatch problem.

Let’s find out what thatch is, how it can help (or harm!) your lawn, how to prevent it, and more.

What is Lawn Thatch?

Thatch is the layer of tightly intertwined organic matter that forms between growing grass and the soil surface. This organic matter is made up of living and dead grass stems, leaves, and roots. It develops naturally over time.

Thatch looks and acts much like a sponge does. Whenever your yard gets wet from rain or irrigation, a lot of the water gets trapped in this thatch layer. When the thatch layer gets too thick, it can cause a whole lot of lawn issues.

The Pros and Cons of Thatch

person dethatching a lawn with a dethatcher
Photo Credit: Ingo Bartussek / Shutterstock / License

Since homeowners typically find out about thatch when it starts causing problems, you might be surprised that it actually has benefits. 

A thin layer of thatch offers these benefits:

Thatch helps insulate the soil. It protects your grass roots from fluctuating temperatures.

Thatch helps keep your soil moist. Since thatch traps water, it can help keep your soil moist for a longer period of time. As long as you don’t overwater your lawn, this shouldn’t be an issue.

Thatch makes your lawn resist foot traffic better. Thatch is spongy and helps soften foot traffic. As a bonus, your lawn feels softer to walk on!

Thatch helps prevent weed germination. Weeds have a harder time sprouting when there’s thatch.

However, too much of anything often becomes detrimental. Thatch is no different; a thick layer of thatch makes your lawn less healthy in the long run. 

Here are the problems that come with too much thatch:

Excessive thatch restricts the movement of air, water, fertilizer, and other important nutrients. It doesn’t only trap water; it also traps other essential building blocks that turfgrass needs to grow strong and healthy, keeping water and fertilizers from reaching the soil. 

Excessive thatch promotes shallow roots. Because all of the nutrients are trapped in the thatch, your grass roots won’t have any incentive to grow deep. A shallow root system makes for an unhealthy lawn; it’s less drought-resistant and has worse cold, heat, and disease tolerance.

Excessive thatch causes soil moisture issues and contributes to lawn diseases. When thatch dries out completely, it’s difficult to get it wet again. It causes problems when it’s too wet too, encouraging fungal growth, inviting lawn diseases, and preventing air from getting to your turf’s root system.

Excessive thatch makes mowing your lawn more difficult. Remember how thatch is spongy and springy? That can cause your lawn mower’s wheels to sink, making your grass blades higher than usual. This makes it easier to scalp your lawn, leading to an ugly, damaging, and possibly uneven cut.

How Thatch Develops

Thatch and a lawn mower
Photo credit: borzywoj / Shutterstock / License

Your lawn is home to more than just your grass and ornamental plants. Some of your lawn’s residents are detrimental, but others are beneficial. Some of these beneficial residents are organisms like earthworms and microbes that decompose organic material. Since thatch is made of organic material, it develops when your lawn produces more organic material than the organisms in the soil can decompose.

Thatch development is a natural process, but the speed at which it accumulates is what homeowners can influence. Bad lawn care practices and lawn management can speed up the process of thatch accumulation. Here are some ways you might be contributing to thatch development:

  • Excessive fungicide and pesticide use. Decomposers are living things that break down organic material. Using too many fungicides and insecticides can kill earthworms, microorganisms, and other decomposers, leading to more thatch.

  • Bad fertilization practices. Typically, bad fertilization technique results in too much nitrogen being introduced to your lawn, which can invite disease. This also promotes fast and vigorous lawn growth, which means it’s producing more organic material that can become part of the thatch layer.

  • Highly acidic soils. While grass typically prefers more acidic over alkaline soils, too low of a soil pH can kill beneficial organisms, resulting in thatch buildup.

  • Soil compaction. Compacted soil isn’t an ideal environment for grass and microorganisms alike.

  • Improper irrigation. Watering your lawn too much will discourage deep root growth. Roots can also contribute to thatch buildup.

  • Bad mowing practices. If you don’t mow your lawn frequently and let it grow tall, you’re more likely to take off more than ⅓ of your turf’s leaf blades. You might get more of the stem, which breaks down slower than the leaves.

Some grasses are more prone to developing thatch, typically those that are more high-maintenance and spread through stolons and rhizomes (or both). Additionally, grasses that have more lignin — a material found in plant cells that’s difficult to break down — produce more thatch. These thatch-prone grasses are:

How to Prevent Thatch

A lot of what you can do to minimize thatch production is to practice good lawn management. Here are some lawn maintenance tips that help prevent thatch:

  • Water deeply and infrequently. Instead of watering for a few minutes every day, water your lawn once or twice a week. Turn on your sprinklers for a longer time to compensate — about 15 minutes should be enough.

  • Fertilize responsibly. Don’t overfertilize! Fertilize your grass with a slow-release fertilizer during your turf’s growing season.

  • Mow your lawn properly. If you mow your lawn often and take off only ⅓ of your turf’s crown whenever you mow, you’ll keep your lawn neat while preventing thatch buildup.

  • Practice grasscycling. Contrary to popular belief, leaving grass clippings on your lawn doesn’t actually contribute to thatch accumulation. Lawn clippings are some of the easiest plant materials to decompose. In fact, using lawn clippings as mulch promotes population growth of beneficial organisms that also get rid of thatch.

  • Maintain the proper soil pH for growing grass. The optimal soil pH for growing a healthy lawn and fostering microbial activity is around 6.0 to 7.0. You can check your soil pH level with a soil test; then, you can adjust the pH by adding lime to your lawn or adding sulfur, as needed.

  • Consider aerating your lawn. Lawn aeration helps your lawn breathe by reducing soil compaction. This promotes healthy grass growth and helps remove some thatch, too.

These tips can also help get rid of thatch. However, if you have a thick layer of thatch, good lawn care practices won’t be able to remove all of it.

How to Check for Thatch

Are you worried about having a thatch problem? Checking the thickness of your lawn’s thatch layer is quite easy; all you need is a trowel and a ruler (if you want to be precise). Here’s how to check for thatch:

  1. Cut out a small plug of grass about 2 inches deep with a trowel or another garden tool.
  2. Look at the plug. You should see the grass, the soil, and a spongy layer of thatch in between them.
  3. Press down on the thatch and measure it. If it’s more than ½ of an inch thick, then you have too much thatch.
  4. Repeat with a few more plugs around different parts of your lawn to check if it’s a problem across your whole yard.

How to Dethatch Your Lawn

Dethatching is the best way to get rid of thatch in your lawn. It involves tearing through your lawn to remove the thatch layer beneath with a dethatching tool, like a dethatching rake, power rake, or verticutter (vertical mower). Here’s a short step-by-step guide on dethatching a lawn:

  1. Water your lawn two days before dethatching.
  2. Run the dethatching machine at least three times across the lawn.
  3. Remove the piles of thatch and dispose of them when you’re finished. 

For a more in-depth look at how to get rid of thatch, you can read our article about when and how to dethatch your lawn.

FAQ About Thatch

When should you dethatch a lawn?

You should dethatch during your turf’s growing season, just before its annual growth spurt. For warm-season grasses, this means you should dethatch in the late spring or early summer. Cool-season grasses should be dethatched from late summer to early fall.

Can you dethatch a stressed lawn?

Never dethatch a stressed lawn! A lawn that’s stressed from drought and high temperatures is weakened and won’t be able to recover from dethatching quickly. This can lead to lawn diseases.

What grasses aren’t prone to thatch development?

Bunch-type grasses don’t really spread, so they’re less prone to thatch development. Some bunch-type grasses homeowners can cultivate in their lawns are tall fescue and perennial ryegrass.

How much does professional dethatching cost?

The national average cost of dethatching your lawn, if you hire a professional landscaping service, is about $190 per hour or between $0.35 and $0.15 per square foot

Dethatch for a Healthy and Green Lawn

While a little bit of thatch is good for your lawn, you’ll need to get rid of it if it becomes too thick. You could do it yourself – you can rent the tools you need if you want to dethatch your lawn DIY. However, it takes quite a bit of time and effort to get it done properly.

So, why not hire someone else to dethatch your lawn? LawnStarter can connect you with capable lawn care professionals in your area that can get rid of that pesky thatch for you. Hire a lawn care pro near you today.

Main Photo Credit: marchenko_family / Canva Pro / License

Janine Caayao

Janine Caayao

Janine Caayao has always been fascinated with growing plants, from fruits and veggies to bonsai trees and orchids. Now, she’s interested in urban gardening with her family. She loves finding new tips and tricks to keep their plants thriving.