Specialized dethatching blades made for lawn mowers can be moderately effective at removing thatch if used properly. To efficiently remove thatch with a mower, choose the correct mower blade type.
- Blades with metal spring attachments can be used to remove light thatch from small yards.
- Blades with nylon trimmer line attachments should be avoided. They damage healthy grass.
- A power rake is much more effective at removing thatch than lawn mower blades. For large or heavily thatched yards, rent a specialized power rake/dethatcher from your local hardware store.
Your lawn mower is designed to cut grass, not remove thatch, so do not expect the same efficiency and quality of work from a mower that you would get from a specialized power rake dethatcher. Renting a power rake is often the best choice to save yourself time, make cleanup after dethatching easier, and get the best results for your lawn.
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How To Tell if You Need to Dethatch
Determining if your lawn needs dethatching is a simple process. Here’s how:
- Dig up a small section of grass, 3 inches square and 5 inches deep.
- Measure the layer of thatch built up beneath the actively growing grass.
- If the thatch layer is greater than 1 inch thick, it’s time to dethatch.
- If the thatch layer is less than 1 inch thick, your lawn does not need immediate dethatching.
Ideal thatch layer thickness is 1/2 inch, but your lawn will still continue to have healthy growth with up to 1 inch of thatch. Dethatching when there is not sufficient thatch buildup can damage your lawn by stripping away roots and rhizomes that your grass needs to store energy.
Can You Dethatch with a Lawn Mower?
It is possible to dethatch with a lawn mower. First, you must swap out your lawn mower blade for a specialized dethatching blade. Then, you must follow the correct procedure to keep yourself and your lawn safe from harm, while at the same time removing as much thatch as possible.
Dethatching with a lawn mower requires care and a lot slower operation than standard mowing. It is best performed on small yards (4,000 square foot maximum). It will not remove heavy thatch but is capable of removing up to 1/2 inch of thatch.
Mower Dethatching Blade Type Guide
Lawn mower dethatching blades come in two common varieties: blades with metal spring attachments and blades with nylon trimmer line attachments.
Blades with metal spring attachments can be effective at removing light-to-moderate thatch from lawns 4,000 square feet or smaller. Correct operation is key to success. These blades must be set to the appropriate height and the spring attachments need to be monitored and replaced as necessary to ensure proper performance.
Dethatching blades with nylon trimmer lines are far less effective at removing thatch. They are prone to causing damage to healthy grass. The nylon line does not discriminate between dead, dormant, and growing grass. These blades should be avoided.
How to Dethatch with a Lawn Mower
In order to dethatch with a lawn mower, you will need to take the following steps to maintain a healthy lawn and get the most benefit from your dethatching blade. Follow these tips for success:
- Change out your standard mower blade for a dethatching blade with spring tines.
- Set the mower height to the tallest setting.
- Test mow a small portion of your yard. Keep moving. If left in one place, a dethatching blade can create “crop circles” by removing large amounts of material in one area.
- Observe the area you’ve test mowed. If necessary, gradually lower the blade height until the blade makes good contact with the yard. The blade is at the correct height when brown, dead thatch is removed but living grass is unharmed.
- Periodically stop mowing and inspect the dethatching blade. Spring tines may be bent or blunted during dethatching. These springs require regular replacement. If the metal tines are bent or broken, they will not effectively dethatch your lawn.
- Wear eye protection and pants when dethatching, as dirt, rocks, and debris may be ejected from the mower chute during operation.
- After dethatching your lawn, use a manual dethatching rake or regular garden rake to gather up the thatch. This can be discarded or added to a compost pile.
Once you’re through dethatching an actively growing lawn, you should see green grass with the topsoil visible beneath, instead of a brown/yellow thatch layer. If your dethatching blade is causing damage to your lawn, stop and adjust blade height, or explore other dethatching options. The key to dethatching lawns safely with a mower is to work slowly and carefully.
Power Rakes vs. Lawn Mower Dethatching
Power rakes and other power dethatchers, such as vertical mowers, are tools designed specifically to dethatch lawns. These tools remove thatch faster, more efficiently, and with less risk of damage to your lawn than lawn mower attachments such as dethatching blades. Not only that, but most dethatcher models provided by rental companies have a built-in bagger, making cleanup a breeze.
A power rake or vertical mower can be rented from your local hardware store. You don’t have to invest in any new equipment or worry about upkeep or storage.
Benefits of Power Rakes
- Remove more thatch than a lawn mower.
- Dethatch more quickly than a mower.
- Reduce the chance of damage to healthy grass.
- Can dethatch larger areas.
- Less prone to damage in uneven or rocky yards than lawn mower dethatching tines.
- Can be rented inexpensively from most hardware stores.
- Most units have a bagger system so dethatching and cleanup is one step.
Professional lawn services companies use power rakes to dethatch lawns because they are simply the best tool for the job. If you have a lawn over 4,000 square feet, it’s best to rent a power rake.
How Much Does it Cost to Rent a Dethatcher?
Rental cost for a power rake or other dethatching tool typically falls between $50–$60 for a 4-hour rental—which is enough time to dethatch a medium to large-sized yard.
While a dethatching mower blade can be purchased for about half that cost, it will not get the job done as quickly or remove as much thatch from your lawn. Renting a power rake is cost efficient because the job will be completed faster and more thoroughly, meaning you won’t have to dethatch again soon.
Is Dethatching the Same as Power Raking?
Power rakes are a type of motorized tool used for removing thatch. They are different than tools advertised as dethatchers. The typical dethatcher is meant for light work and can remove about 1/2 inch of thatch. Power rakes, like the name implies, are motorized versions of dethatching rakes. They can remove several inches of thatch at once.
Do Dethatching Mower Blades Work?
If your yard is small and has light thatch, a dethatching mower blade with spring tines might be the right tool for the job. They’re inexpensive and, when operated properly, can get the job done. Just be sure to choose the right dethatching blade. Avoid models with nylon string that are marketed as dethatchers. These are lawn destroyers.
If you have a large yard, heavy thatch, or are struggling with bent spring tines (dethatching blades may be damaged in uneven or rocky lawns), your best bet is to rent a power rake from your local hardware store. The cost is somewhat higher but you will get better dethatching results with less potential damage to your lawn.