Is your grass struggling to grow? Is it turning brown even when you regularly water it? Is there a thick layer of living and dead detritus swallowing up the grass blades?
Well, it might be time to dethatch your lawn.
What Is Thatch?
Firstly, thatch is the layer of living and dead grass shoots, stems, and roots that builds up between the grass blades and the soil. Take a look at the image below to see what thatch looks like and where it is located:
What is Dethatching?
Dethatching is removing that layer of thatch to help your grass grow. When thatch grows more than ½” thick, it can suffocate your grass, preventing moisture from reaching the soil and preventing the grass from getting enough sunlight.
Here is a photo of what dethatching a lawn looks like:
The Pros of Dethatching Your Lawn
- Helps water, nutrients, and oxygen to penetrate the soil, which your grass needs to live.
- Reduces fungal diseases in your grass by preventing the anaerobic conditions in which fungal disease thrives.
- Reduces pest pressure as pests can’t inhabit and eat the thatch.
- Allows compost to reach the soil where the soil microbiology can break it down to feed the grass.
- Removes dead grass.
- Allows new grass seed to reach the soil to germinate.
The Cons of Dethatching Your Lawn
- Thatch that’s less than ½” thick actually helps your lawn as both a mulch and a compost. The mulch keeps your grass shaded so you need to water less, and the beneficial microbes and worms in the soil will break down the thatch into nutrients that benefit your grass which means less fertilizer needed.
- Dethatching stresses out your lawn as it will cut the grass. Done at the wrong time of year, when the grass is dormant, heat-stressed, or slowly growing, or when the soil is too dry or too wet, you can seriously damage or kill your lawn.
- If the soil is compacted and the thatch is in the grey zone of dethatching (between ½” and 1”), then core aeration is a better bet. Core aeration will ease the compaction and remove some thatch for you. (Don’t use a spiked device, as it’ll compact the soil around the hole.)
- Dethatching can be labor intensive or expensive, depending on your method. You can dethatch with a rake (if you have a small lawn) or by renting a power rake/dethatcher (if you have a bigger lawn or a lot of thatch). The power rake will run you between $70 – $100 to rent for a half or full day.
Do You Really Need to Dethatch Your Lawn?
You Don’t Need to Dethatch Your Lawn If:
- The layer of thatch is ½” thick, as it benefits your lawn by providing mulch and organic matter.
- Soil compaction is the root cause of your lawn’s stunted growth. In that case, you’ll want to aerate your lawn. Wondering if you should aerate or dethatch? Read our article “What is The Difference Between Dethatching and Aerating?”.
You Do Need to Dethatch Your Lawn If:
- The thatch layer is more than ½” thick, as the mats of slowly decaying thatch will create mats and anaerobic conditions where fungal disease and lawn pests thrive.
- You plan to overseed or add compost and the thatch layer is preventing the seed or compost from reaching the soil.
Dethatching General Rule of Thumb:
| Thatch Layer Less than 1/2 Inch | Dethatching is NOT Required |
| Thatch Layer More than 1/2 Inch | Dethatching is Required |
Can You Prevent Thatch Buildup?
Excessive thatch buildup is not a natural phenomenon. In the long run, by addressing the root causes and switching over to organic lawn care methods, you’ll not only never have to dethatch again and your lawn will be a lot healthier and easier to take care.
Prevention Tip 1: Use Compost Instead of Synthetic Nitrogen
Synthetic nitrogen creates thatch by 1) causing grass to grow too fast, creating more root and leaf build up as a byproduct and 2) destroying the beneficial microbes in the soil that would otherwise break thatch down into nutrients your grass would benefit from.
The solution is to switch to compost for your fertilization needs. You can still grow beautiful, lush grass but the lower amounts of nitrogen in compost will mean your grass won’t burn and won’t grow as fast. This also means you’re free from excessive mowing! Woo hoo!
Compost also supports beneficial microbes by adding organic matter into your soil that the microbes digest into usable nutrients. This means your soil becomes healthier, the beneficial microbes decay thatch before it becomes a problem, and your grass is healthier in the long run.
Compost also has other benefits for your lawn. To learn how to switch over, check out our guide on how to add more organic matter to your lawn.
Prevention Tip 2: Seed with Grasses Less Prone to Thatch
Certain grass species and cultivars are more prone to thatch than others. Kentucky bluegrass, creeping red fescue, and creeping bentgrass form thatch faster than other species. Stoloniferous grasses, where the grass spreads by overground roots, also contribute to more thatch.
Other grasses produce less thatch, like perennial ryegrass and tall fescue. Overseeding these grass species will reduce the amount of thatch being produced. They’re less aggressive growers, but they’re hardier, lower maintenance grasses that will seriously cut down on the amount of lawn care you need to do.
Is There a Good Time of Year to Dethatch Your Lawn?
The best time of year to dethatch your lawn is when it is growing most vigorously and the soil is moist, as dethatching can leave your lawn looking ragged and your grass stressed.
- For cool-season grasses, that means spring or autumn.
- For warm-season, that means during the heat of summer.
How Often Should You Dethatch Your Lawn?
How often you should dethatch your lawn highly depends on the type of grass you have. Some types of grasses, such as Kentucky Bluegrass, Creeping Bentgrass, Bermudagrass, and Zoysiagrass, are more prone to thatch buildup and require yearly dethatching.
Other grasses, like rye or tall fescue, may only need to be dethatched every 3 to 5 years,. It’s possible your grass doesn’t even need to be dethatched if the buildup is so small.
To determine if your lawn even needs to be dethatched just check it a couple times a year to see if the thatch buildup crossed the 1/2 inch amount. If the thatch layer is more than half an inch thick, it’s time to consider dethatching!
Can Dethatching Harm Your Grass?
Dethatching may be a necessary process for maintaining your lawn, but it also comes with the potential risks you should be aware of. It’s important that you understand the risks and take the right steps to minimize them when deciding to dethatch your lawn. Here are the potential risks of dethatching:
Damage to the Root System
Dethatching involves the removal of dead grass and accumulated organic matter, which can sometimes result in unintentional harm to your grass root system. When dethatching is done too aggressively or with the wrong equipment, vital roots can become immensely damaged, this can cause stress on the grass and stunt the grasses growth.
To lower the risk of root damage follow these tips:
- Use the appropriate dethatching equipment for your lawn type and size.
- Adjust the dethatching depth to an appropriate level for your grass species.
- Perform dethatching during the grass’s growing season to allow for quick recovery.
Soil Compaction
Another possible risk when dethatching your lawn is soil compaction. When heavy equipment is used or you dethatch too often, the soil can become compacted down, which can limit the flow of water, air, and nutrients to your grass roots. Compacted soil can seriously damage your grasses health, and will make your lawn more susceptible to diseases and even pests.
To help reduce the risk of soil compaction from dethatching follow these tips:
- Avoid using heavy equipment on wet or saturated soil conditions.
- Use aeration techniques along with dethatching to alleviate soil compaction.
- Apply organic matter, such as compost, to improve soil structure and reduce compaction.
Read our related post “What is Soil Permeability?” here.
Erosion
Dethatching can also lead to soil erosion, especially on lawns with sloped surfaces, and most likely lawns that receive heavy rainfall. When dead grass and organic matter are removed, soil may be left exposed and its more likely to wash after a heavy rainfall.
To prevent erosion in your lawn after your dethatching follow these tips:
- Apply a layer of straw or other organic mulch to protect exposed soil from erosion.
- Avoid dethatching during periods of heavy rainfall or high winds.
- Consider planting a cover crop to help stabilize the soil and reduce erosion risks.
Are there Alternatives to Dethatching?
While dethatching can be a very effective method to remove the thatch buildup your lawn has been accumulating, there are other alternative ways that can help with your lawn issues. These alternatives include overseeding, aeration, and top-dressing.
Overseeding
Overseeding is the process of sowing grass seed directly into an existing lawn without having to remove the current grass. This can help to fill in thin or bare spots, and it can also help keep weeds away. Make sure you choose the same type of seed that matches your lawn’s grass species.
- Select the appropriate seed mix for your lawn.
- Rake the lawn gently to create a good seed-to-soil contact.
- Spread the seed evenly according to the recommended seeding rate.
- Water the lawn consistently to support germination and establishment.
Aeration
Aeration is another method that can help fix your lawn problems with thatch and soil compaction. Aeration is done by removing small cores/plugs of soil, which allows air, water, and nutrients to get deep into the root layer of the grass.
Read our related post “What is The Difference Between Dethatching and Aerating?” here.
Top-Dressing
Top-dressing is applying a thin top-layer of compost, sand, or a soil mixture to the lawn. This can help promote a healthy soil structure, improve your lawns drainage, and encourage microbial activity which can help break down thatch.
Read our related post “Can You Add Topsoil on Top of Grass? Topsoil Guide” here.
What’s the Verdict, Should I Dethatch My Lawn?
If your lawn is building up a thick layer of thatch, and your lawn is at its height of the growing season, you should dethatch your lawn. If there’s only a small layer of thatch through which oxygen and water easily move, then don’t. You’ll stress out your lawn for no reason.
How to Dethatch Your Lawn Fast and Cheap?
Although this article focuses on the pros and cons of dethatching, I will still quickly explain how you can dethatch your lawn for cheap.
The best way to dethatch your lawn without renting heavy duty equipment or spending hours raking is to use the Greenworks Electric Dethatcher. It is a low cost machine that will save you a lot of time, and time is valuable when it comes to lawn care. I hate spending hours doing something I know a machine can finish in a matter of minutes.
The Greenworks electric dethatcher has a bunch of metal spring tines that dig down into the thatch layer and bring it to the surface. You’ll be amazed, your lawn may not look like it has thatch but once you start going the hidden layer surfaces.
Just like a lawn mower, push the dethatching machine along your entire lawn until you successfully dethatch your entire lawn.
When you are finished you will have all the thatch sitting on top of your lawn, you need to clean it up. If you have a lawnmower that collects grass you can simply go over your lawn to pick it up, just make sure to empty the bag a couple times as it fills up quickly. If you don’t have a grass collecting mower you’ll have to rake it up.
I recommend you watch this video by Silver Cymbal where he shows you exactly how to dethatch a lawn using the Greenworks electric dethatcher, check it out:
I hope this guide was helpful and you learned a lot more about dethatching. If you have any questions about your lawn please ask them in our comment section below.
Jamie is the founder of The Backyard Pros. When he was 15 years old he started working at a garden centre helping people buy plants, gardening products, and lawn care products. He has real estate experience and he is a home owner. Jamie loves backyard projects, refinishing furniture, and enjoys sharing his knowledge online.