How to Dethatch a Lawn

Thatch is something that drives homeowners crazy. It turns their otherwise beautiful lawn into an eyesore. But what drives us crazy is that many people don’t realize that thatch problems are entirely avoidable.

What we’re trying to say is that improper lawn care is the reason that thatch becomes a problem. You shouldn’t have to worry about thatch on a healthy lawn. That’s why we’re going to show you how to dethatch a lawn, but more importantly, how not to get thatch problems in the first place.

What is Lawn Thatch?

Thatch isn’t a bad thing in itself. Your lawn will naturally form a layer of living and dead organic matter at the base of the grass plant called thatch. And this layer acts as protection for your grass against wear, insulation for the soil, and a shield against water evaporation so your lawn can stay hydrated.

In other words, thatch is needed to keep your lawn healthy. But then, if you start to get too much thatch – more than 1” – it becomes unhealthy and harmful to your lawn.

Why Dethatch a Lawn?

When thatch becomes too thick, you can’t feed your lawn because water, air, and fertilizer aren’t allowed to pass through. Besides starving, your grass becomes vulnerable to pests and diseases. Soon enough, you’ll be facing a completely dead lawn.

Simply put, excessive thatch will kill your lawn. That’s why you want to dethatch a lawn when there’s too much.

What Causes Thatch?

So what causes excessive thatch? We thought you’d never ask! As we mentioned earlier, improper lawn care is the culprit. That means, first and foremost, using synthetic fertilizers.

Synthetic Fertilizers

The problem with synthetic fertilizers is twofold. The first is that these nitrogen-packed products cause grass to grow unnaturally fast. And when you get this imbalance where grass is added faster than it can decompose, you’ll get an excessive layer of thatch.

The second problem with synthetic fertilizers is that they do not feed the soil in a wholesome way that would allow microbial life to thrive. Without those beneficial microbes to breakdown thatch, guess where it’s going? Nowhere! You’ll end up with a thick layer of thatch and soil that’s as good as dead.

When you buy fertilizer, check the label. If it says synthetic, put it back on the shelf. If it says organic, run to the cashier. OK, you can walk too.

Improper Watering

The proper way to water a lawn is to do so deeply – ensuring that soil is moist 4 to 6 inches deep – and infrequently. The improper way would be to water shallow and frequently, say every day or every other day.

XLUX Soil Moisture Meter
Don't have laser vision? That's OK. This moisture meter, inserted 4 to 6 inches deep, will tell you if your grass needs watering.

Shallow and frequent watering means that your soil will only be wet near the top. So you end up encouraging the roots of your grass to grow near the top where all the water is, rather than getting them to establish themselves deep into the soil.

By watering right, you discourage roots from contributing to excessive thatch, and encourage the growth of long, strong roots for a healthy, green lawn.

Improper Mowing

Many people think of thatch as just dead grass. So they think that grass clippings equals thatch, and they remove it after they mow. Not true and not good!

When you consider all the things we talked about so far, you’ll realize that thatch is a result of more than just grass clippings. That said, grass clippings can contribute to thatch if your lawn isn’t mowed properly.

Mowing improperly means cutting too much of the grass blade at once. Not only does that make it harder for the clippings to decompose fast, it will reduce photosynthetic activity in the remaining blades. When mowing grass, you should follow the “one-third rule” of cutting no more than one-third of the grass blade at once.

Also, using a mulching mower – which minces grass clippings – helps tremendously with decomposition. It can help you avoid excessive thatch, especially when you waited too long to mow your lawn.

Sun Joe 24V-X2-17LM Mulching Lawn Mower
The single most important thing you can do when it comes to caring for your lawn is to get a mulching mower so that you can cut, mulch, and help the clippings decompose fast.

Grass clippings play a huge role in feeding your lawn with essential nutrients, so you should definitely leave them on your lawn. Just remember to mow properly and use a mulching mower to make sure those grass clippings never become a problem.

Pesticide Use

And finally, the use of pesticides is a huge contributor to excessive thatch. That’s because pesticides wipe out earthworms and beneficial microbes that are necessary for decomposing thatch.

The reason why you need to use pesticides is because you have an unhealthy lawn, but using pesticides not only creates excessive thatch but damages your lawn further. Check out our tips on how to grow a healthy lawn so that you never have to use pesticides.

How to Remove Thatch

As promised, we’re going to show you how to remove thatch. But remember, this’ll only solve the symptoms. If you want the cure, promise us to take care of your grass properly!

Use an Aerator (Best Way)

In our opinion, the best way to remove thatch is to aerate your lawn. This involves pulling plugs of soil (we like to call them wine corks) out of the ground. Aerating not only physically removes thatch, but loosens compacted soil and opens it up for water, air, and fertilizer to get through. You should aerate your lawn every two or three years as part of a healthy lawn care program.

Yard Butler Lawn Aerator
You can rent a power aerator from your local home improvement store. Or you can hire a lawn care company to aerate your lawn. This manual aerator is also a handy tool to have. You can aerate your lawn at anytime without the need for heavy machinery.

Leave the plugs on the ground. They contain a lot of yummy nutrients for your lawn. You can use a rake to break them down a bit and spread them out.

After dethatching with an aerator, spread compost and organic fertilizer over your lawn before overseeding to rejuvenate your lawn. Keep the grass seeds moist by watering lightly every day – but don’t drown them in water – for the next few weeks to allow them to germinate.

Use a Dethatcher

A dethatcher (also known as a power rake) works differently than an aerator. Rather than removing the soil, a dethatcher only pulls out debris in the thatch layer. This would be a good tool for doing a bit of thinning and freeing up the soil.

But you have to be careful not to scalp your lawn, which means creating bald spots in your lawn by getting too close to the ground. Normally, we’d tell you to leave grass clippings on the lawn, but you’ll want to remove the debris that comes from dethatching.

When Should You Dethatch?

Timing is important. The rule of thumb is to remove thatch only when the grass is actively growing, rather than being in their dormant state. You should also avoid dethatching when your grass is showing signs of stress. That would be like rubbing salt into the wound.

If you have cool-season grass – or live in the upper two-thirds of the US – you want to dethatch in the late summer or early fall. If you have warm-season grass – or if you live in Florida, Louisiana, Texas, etc. – you should dethatch in late spring.

Remove Thatch for Good

The best way to remove thatch isn’t with any product or by doing anything to your lawn. It’s by having a healthy lawn and doing nothing! You shouldn’t have to remove thatch on a healthy lawn as the thatch would self-regulate.

So use organic fertilizer, mow right, water right, and say goodbye to thatch problems forever!

Have Fun Out There!