Difference Between Dethatching and Aeration

Worker walking behind a gas-powered aerater

Whether your lawn is losing its luster or weeds are speckling its once-perfect complexion, it may need a spa day that involves more than just regular mowing and watering.

Dethatching and aeration are two of the best pampering treatments you can do for your lawn to get it back to its healthy, glowing self. But before hiring a dethatching and aeration service provider, you must first understand the difference between dethatching and aeration.

Difference between dethatching and aeration

It’s easy to understand the difference between dethatching and aeration, as their names already offer clues. Dethatching fixes thatch problems, while aeration loosens lawn soil and fixes compaction problems – giving your soil more air.

Whether your lawn is spongy and diseased or rock-hard and patchy, dethatching and aeration are long-lasting treatments that can work together or separately to improve the flow of nutrients to roots.

Dethatch for thick thatch problems

Like how a good dandruff treatment rakes up dead skin from your scalp, lawn dethatching rakes up excessive debris and organic matter sitting on your soil’s surface.

A thin layer of thatch is actually healthy for your lawn. It provides nutrients for earthworms and beneficial microbes, and it insulates soil during extreme temperature shifts. However, thatch becomes a problem when it’s more than half an inch thick.

If your lawn’s soil surface is covered in a thick layer of thatch, it’s a symptom of larger lawn and soil problems that will need to be fixed to prevent an ongoing thatch problem.

illustration explaining thatch on grass
Infographic by Juan Rodriguez

The problem: Thick thatch acts as a barrier against sunlight, water, oxygen, and nutrients. It diminishes soil quality and stifles root growth.

The solution: Dethatching is the process of vigorously raking up excess thatch (the layer of dead grass, leaves, and other organic matter between grass blades and the soil surface) to give soil and grass roots access to water, oxygen, sunlight, and nutrients.

Aerate for compacted soil issues

Aeration is like acupuncture for your lawn, but instead of thin needles, aerators have hollow tines that poke small holes and remove soil. When you aerate your lawn, you help loosen its tight muscles and encourage better circulation of oxygen and nutrients.

illustration showing good soil vs compacted soil
Infographic by Juan Rodriguez

The problem: Compacted soil restricts root growth and prevents the root zone from receiving water, oxygen, and nutrients from the soil surface.

The solution: Core aeration (also known as plug aeration) involves poking out small cores of soil from your lawn to relieve soil compaction, give roots space to grow, and increase the flow of nutrients, water, and oxygen to roots.

While dethatching removes the layer of thatch above the soil surface, aeration removes actual plugs of soil from your yard.

  • With looser, more nutrient-rich soil, root systems can spread out and grow deeper into the soil.
  • Holes in your yard may not be glamorous, but they’ll quickly fill in with dense, healthy new grass.
  • Aeration actually decreases your need to dethatch. Looser, less compacted soil stimulates beneficial microbe growth, which helps decompose the thatch layer.

Signs your lawn needs dethatching or aeration

Does your lawn have both thatch and compaction problems? With excess thatch and soil compaction come a host of lawn symptoms. These symptoms can give hints on what’s wrong with your lawn and help you decide which treatment it needs.

Signs your lawn needs dethatching

Your lawn may need dethatching if:

  • The ground is spongy and springy to the touch.
  • Grass blades are weak.
  • Dry spots are appearing on your lawn, and the grass is thinning.
  • Weeds are invading your lawn.
  • The grass is losing its healthy, green color.
  • Your lawn is developing an insect problem.
  • Your lawn is more sensitive to temperature extremes.
  • Fungal diseases are infecting your lawn.

Signs your lawn needs aeration

Your lawn may need aeration if:

  • The soil feels hard to the touch.
  • Your turfgrass is thinning or growing slowly.
  • The grass is developing diseases like brown patch.
  • Your lawn isn’t draining properly during rainstorms.
  • The grass is turning yellow.
  • Weeds are invading your lawn.
  • Trees and shrubs are showing symptoms of stress (wilting, leaf scorch, early fall color, or dieback).

If your lawn has both a spongy brown carpet and rock-hard soil, it’s a great idea to give it the full spa treatment. But remember to dethatch before you aerate. Dethatching removes debris to make lawn aeration a whole lot easier and less time-consuming.

Note: Symptoms of thick thatch and compacted soil can be quite similar. To confidently diagnose your lawn, check your lawn’s symptoms and then use the tests below.

Dethatching and aeration tests

Testing whether your lawn is thatchy or compacted is a piece of cake.

How to find out if your lawn needs dethatching

To check if you have a thatch problem, simply take a sample of your lawn and measure thatch depth:

  1. Dig a 3-inch-deep hole in your yard and remove a small slice of soil.
  2. Measure the brown, spongy thatch layer between the grass blades and the soil surface.
  3. If the thatch layer is over half an inch long, your lawn could use dethatching.

Alternatively, you can press a stick, a ruler, or your finger into the thatch layer. Measure how deeply you can push into the spongy layer before you reach the soil. If you can push more than half an inch, it’s time to dethatch.

How to find out if your lawn needs aeration

If your lawn has a shallow root depth, it may indicate soil compaction. Do the following to confirm:

  1. Cut out a small section of your lawn that is at least 6 inches deep.
  2. Using a ruler, measure how deep the roots are.
  3. If the grassroots are only growing 1 to 2 inches deep, your lawn needs aeration.

You also can test whether your soil is compacted using the screwdriver test. It’s not as reliable as a full cross-section, but it’s a quick, helpful indicator of compaction. If you can easily push a screwdriver 3 inches into moist soil, then you probably don’t have a compaction problem.

When to dethatch and aerate your lawn

Your schedule for dethatching and aerating depends on where you live and the type of grass you have.

When to dethatch your lawn

It’s important to dethatch during your region’s growing season to minimize lawn stress.

  • For cool-season grasses (grown in the northern parts of the U.S.) like Kentucky bluegrass and creeping red fescue, dethatch your lawn in early spring or late summer to early fall.
  • For warm-season grasses (grown in the southern parts of the U.S.) like Zoysia and bermudagrass, dethatch your lawn in late spring to early summer.
  • If you live in the transition zone (the middle slice of the country extending from California to Virginia) or want specific advice for dethatching in your region, it’s a good idea to contact your local extension office.
illustration showing the cool and warm season grasses on the US map, along with the transitional zone
Infographic by Juan Rodriguez

Pro tip: Avoid dethatching when your lawn is dormant or stressed. Also, don’t dethatch in the peak of summer heat or during a drought, as this can severely damage your lawn.

How often to dethatch your lawn

You’ll only need to dethatch if thatch becomes an issue. As long as the thatch layer stays thin, nutrients can reach the soil, and the grass can grow thick and healthy.

With proper lawn care maintenance and grass seed that isn’t prone to thatch, you may only need to dethatch your lawn every few years. However, some grass species like bermudagrass, bentgrass, and Kentucky bluegrass build a thick thatch layer and will likely need annual dethatching.

When to aerate your lawn

Just like dethatching, you’ll want to aerate during your region’s growing season to ensure your grass quickly recovers.

  • For cool-season grass lawns, fall is the ideal time to aerate. While cool-season lawns can be aerated in either early spring or early fall, fall aeration is preferred. Most weeds are not actively germinating in fall, so they’re less likely to sprout in the holes.
  • For warm-season lawns, aerate in late spring or early summer for swift grass recovery. To avoid lawn stress, do not aerate at the peak of summer heat.

How often to aerate your lawn

Since aerating is preventative, it’s usually done annually. However, your soil type will determine the best routine for your lawn.

  • If you have sandy soil with few drainage issues, you’ll only need to aerate every two or three years.
  • If you have heavy clay soil or if your lawn has a lot of heavy foot traffic, it’s a good idea to aerate every year or even twice a year.

Dethatching and aeration methods

Let’s explore the methods used to rejuvenate and optimize your lawn’s health and vitality. Discover the strategies that best suit your specific needs and bring new life to your turf.

Dethatching methods

Agri-Fab tine dethatcher pulled by a lawn tractor
Agri-Fab, Inc. | Wikimedia Commons | CC0 1.0

Dethatching involves forcefully raking thatch from your lawn. Dethatchers have curved metal blades that slice into your thatch and pull it up. You can adjust the blades to best suit the amount of thatch buildup in your lawn.

Depending on your lawn size and thatch level, you can use either of the following: 

1. Manual dethatcher

Also known as a thatch rake, a manual dethatcher is a rake with short, curved steel blades that cut into thatch and pull it up. With this method, you’ll be raking your lawn with more effort and muscle involved.

Best for: Small lawns with a mild thatch problem

2. Electric (corded) dethatcher

These dethatching machines look like small lawnmowers and have rotating wire tines that pull up thatch. You can use a dethatcher like a mower, making two or three passes across your yard (perpendicular to each other).

Best for: Medium lawns with a mild to moderate thatch problem

3. Power rake

Power rakes are large, mower-like machines with knife-like tines (flail blades) that rotate on the bottom of the machine, perpendicular to the ground. You can make two or three passes across your lawn with a power rake, but be careful not to scalp your lawn. Check to ensure you’re not tearing out the roots as you go.

Best for: Large lawns with a moderate to severe thatch problem

4. Vertical mower

Also known as a verticutter, this vertical mower has flat, vertical discs that slice down through the thatch and into the soil, creating grooves in your soil. Make two passes across your yard with the correct blade spacing and depth for your grass type and thatch level.

Best for: Large lawns with a serious thatch problem

After you’re done dethatching, give your grass special care:

  • Rake up the debris and compost it
  • Fertilize
  • Water
  • Overseed (if you’re not planning to aerate) to give your lawn an extra boost

Aeration methods

macniak | Canva Pro | License

Core aerators have hollow tines that poke holes into the ground every few inches, uprooting plugs of soil that then decompose on your lawn.

Though other styles of aeration (such as spike aeration) exist, lawn care professionals and homeowners prefer core aeration for long-lasting, effective treatment.

To aerate your lawn, you can choose to use any of the following: 

1. Manual core aerator

A manual core aerator is a simple, inexpensive aeration option. It looks similar to a pogo stick, with a T-shaped handle, long steel body, foot bar, and two (or more) hollow tines that pierce the ground. Using a manual core aerator, you’ll poke holes 2 to 3 inches apart.

Best for: Small yards and areas that need spot aeration

2. Gas-powered, push-behind core aerator

Most homeowners choose to rent a push-behind aerator for a few hours or a day. Push-behind aerators look similar to lawnmowers and will do most of the muscle work for you. Give your lawn at least two passes, “mowing” north to south first and the second time east to west.

Best for: Larger lawns with heavy compaction

3. Tow-behind core aerator

If you have a riding mower, tow-behind aeration is a relatively hassle-free way to deeply exfoliate your lawn. Tow-behind aerators have hollow tines that spin like soil-filled wheels as they move. Drive your lawn tractor across your lawn in overlapping lines at the slowest engine speed, increasing the speed if conditions permit.

Best for: Large lawns with heavy compaction

Keep in mind to do the following after aeration:

  • Leave the cores of soil on your lawn. Cores act as natural topdressing, giving your lawn a nutrient lift.
  • You also should apply fertilizer and compost. Rake compost into the holes to give your roots a treasure trove of nutrients.
  • To encourage dense grass growth, this is the perfect time to overseed.
  • You’ll also want to water your lawn every two to three days for the next two to three weeks.

Benefits of dethatching and aeration

picture of a lawn after aeration
Aerated Lawn
ArtBoyMB | Canva Pro | License

Dethatching and aeration aren’t just quick lawn beauty fixes. They’ll give your lawn lasting health benefits, too.

Benefits of dethatching:

  • Gives grassroots access to nutrients, water, and air
  • Improves soil health and nutrient density
  • Exposes lower grass shoots to more sunlight
  • Improves grass health and curb appeal
  • Increases root strength and depth and encourages root growth
  • Reduces susceptibility to disease, fungus, and pests
  • Increases drought and heat tolerance
  • Improves the effectiveness of fertilizer, so you can use less of it
  • Reduces water usage
  • Helps control weeds
  • Decreases stormwater runoff
  • Reduces puddling and standing water
  • Helps winterize your lawn and prepare it for spring growth
  • Reduces the potential for mower scalping

Benefits of aeration:

  • Improves grass health and root growth
  • Increases curb appeal
  • Helps prevent erosion
  • Decreases susceptibility to disease and pests
  • Cuts down on dethatching needs
  • Increases drought tolerance
  • Reduces water usage
  • Decreases the need for fertilizer
  • Helps control weeds
  • Reduces runoff
  • Decreases the appearance of puddles and standing water
  • Helps winterize your lawn
  • Increases the population of beneficial organisms like earthworms

FAQ about dethatching and aeration

Can core aeration remove my thatch?

Core aeration removes some thatch because it involves extracting cores of soil, which include thatch and grass. However, the Michigan State University Extension advises that aeration “will not provide the quickest remedy” to a thick thatch problem. If thatch is your main lawn concern, you’ll want to choose dethatching over aeration.

Can I apply herbicide after aerating?

It depends on whether or not you’re planning to overseed. If you won’t be overseeding, apply a pre-emergent herbicide to prevent pesky weeds like crabgrass from growing in the holes.

If you’re planning to overseed your lawn after aerating, hold off on a broad herbicide application. Synthetic herbicides can harm new seeds and stunt young grass growth. For a healthy lawn, spot spray if weeds emerge.

Should I mow my lawn right before or right after I dethatch or aerate?

Mow your lawn right before you dethatch or aerate. You’ll want to cut it a bit shorter than usual – mow it by half (rather than one-third) of its height.

Give your lawn the spa treatment

If your lawn isn’t looking as lively and lovely as it used to, dethatching and aeration are lasting solutions to rejuvenate your grass and get it back to its lush, glowing self.

If you don’t want to go the DIY route, call a local lawn care pro to take care of all your dethatching and aerating needs. You can take the day off and get your own spa treatment – with no raking or soil involved.

Main Photo Credit: Guipozjim | Wikimedia Commons | CC BY 3.0

Melanie Joseph

After discovering her passion for writing through her beauty blog, Melanie left her engineering job in California, became a writer, and never once looked back. When she isn't writing, she loves dipping in the pool, tending to the garden, or doing simple home improvement projects.