Dethatching Your Lawn in Fall

A lawn with autumn leaves.

Excess thatch in the lawn can really do some damage to the overall look and health of your grass. Although the dethatching process is relatively straightforward, it's important to remove thatch at the right time to avoid damaging the lawn even further. Here's a quick guide to dethatching your lawn in the fall.

What Is Thatch?

Thatch is simply a layer of rhizomes and grass roots that clump up over time. Contrary to popular belief, thatch is not caused by excess grass clippings. All grass develops some thatch, though thatch accumulates at different rates depending on the type of grass. Although it's good to remove excess thatch, a small portion of thatch is actually healthy for the lawn. You have a thatch problem when the layer is thicker than half an inch and water is having trouble getting to the grass roots.

Fall Dethatching

Fall is actually one of the best times to dethatch your lawn because there is plenty of time for the grass to recover. It's always recommended to dethatch when the soil is fairly moist and the grass is actively growing. Dethatching at the wrong time can significantly damage your lawn because it will not have proper time to recover.

Dethatching Tools

For small lawns, you can use a special dethatching rake to remove excess thatch. You can also rent a power rake or dethatcher for larger lawns. These are also referred to as verticutters or vertical cutters and are typically gas or electric-powered. Because you generally only dethatch once a year, it's usually more cost-effective to rent vertical cutters than purchase them outright.

Step 1 - Mowing

A lawn mower cutting grass.

Before you take your dethatching tool to the lawn, you need to mow the grass first. You should cut the grass down to around half its normal height for best results. Cutting the lawn ahead of time will make the dethatching process easier because you do not have to fight long grass blades to remove the thatch. If you do not cut the grass, then you run the risk of getting the rake tangled in the blades.

Step 2 - Mark Lines

If you are using a power dethatcher, make sure you properly mark any irrigation lines running on your property before you start. You should also note any underground utility lines and sprinkler heads as the dethatcher can damage these in the process.

Step 3 - Dethatching Rake

A rake dethatching a lawn.

A dethatching rake is used just like a normal rake. The tines of the tool will dig out the thatch and pull it through the upper layers of grass. As you rake, you should notice the thatch start to separate from the ground. Once you're finished raking, simply place the thatch in a garbage bag and dispose.

Step 4 - Power Dethatcher

A power dethatcher is ideal for larger lawns. They are a little more expensive than a rake, but they will save you a lot of time. When you rent the dethatcher, ask the store to adjust the cutting depth and spacing before you leave. The blades should reach a depth of around half an inch into the soil. If you cut too deep, you can damage your lawn. It's also recommended to read the manual for the dethatcher and follow the directions carefully before use.

Step 5 - Lawn Repair

A bright blue and orange rake against a lawn.

Your lawn will look pretty bad after you dethatch it. To finish the job, it needs to be raked thoroughly—with a normal rake, not a dethatching rake. If you notice any bare spots, then you should use a patching seed to repair them.

Step 6 - After Care

After you've removed the thatch from your lawn, it's prime time to fertilize. Avoid fertilizing before the dethatching process because you will likely remove a lot of the fertilizer by the time you are finished. You should also water your lawn frequently to encourage the grass to recover.