Aerating vs. Dethatching: Which is Better for Your Lawn?

Kenneth Wilson

Proper maintenance is essential in keeping your lawn green and healthy. This includes two of today's most popular lawn care maintenance: aeration and dethatching. While both are ideal for improving and maintaining the good health of your lawn, there are specific differences between the two that you need to be aware of.

Dethatching removes a thick layer of thatch on the topsoil, whereas aeration breaks up and treats the soil. Dethatching can take a toll on the grass. Meanwhile, aerating is a much-simpler process that encourages a quick healthy lawn rebound.

Let's discuss the differences between aeration and dethatching so you can determine the best option for your lawn care needs.

What is Aeration?

The aeration process loosens the soil, releases the pressure in compacted soil, and enables the grass to get more access to various necessary nutrients. This encourages healthier root growth. (Related: Lawn Aerator: What Is It And Do You Need It?)

Aeration involves removing small plugs of soil from the land's surface and letting the remainder breathe. Keep in mind that compacted soil happens because of several reasons. And when that happens, water cannot get through the earth as intended, which may affect the growth of the grass.

Some telling signs that your lawn needs to be aerated:

  • There is heavy foot traffic on your lawn. This speeds up the possibility of soil compaction.
  • The yard tends to dry out pretty quickly and has a spongy feel when walked on. It can indicate a thatch problem, where water cannot disperse into the soil properly.
  • Puddles frequent your yard throughout. Any pools of water are a telling sign that the water has problems dispersing into the soil.
  • Once the aeration process is completed, you must follow lawn care activities such as proper fertilizing, mowing, and watering.

Benefits of Aeration:

  • It helps improve grass health and encourages healthy root growth
  • It increases your curb appeal
  • It reduces erosion
  • It lessens the need for fertilizer
  • It enables you to save water
  • It controls pesky weeds
  • It decreases your lawn's susceptibility to disease and pest infestation
  • It minimizes your dethatching needs
  • It increases your lawn's tolerance to drought
  • It reduces runoff
  • It decreases the occurrence of puddles and standing water
  • It helps in winterizing the lawn

What is Dethatching?

On the other side of the coin, the dethatching process removes the excess "thatch," which refers to a layer of dead grass, leaves, and roots on the soil surface. You will need to ensure only a healthy layer remains atop.

Once thatch growth on a lawn goes out of control– it forms a thick cover that stops water and air from reaching the soil's depth. This will suffocate the roots and ultimately kill off the grass. Lastly, it may also protect the ground from extreme temperature changes.

Important Note: Having a small amount of thatch can be healthy and beneficial for your yard, as a think layer makes it more resilient against daily wear and tear. It also keeps the soil moist and supplies nutrients to it.

Excessive thatch buildup can result in several issues:

  • It encourages the presence of disease-causing fungi and insects
  • It holds on to humidity, and too much moisture may only promote diseases
  • It restricts root growth and movement of air, water, and nutrients in your soil

Common factors that cause heavy layers of thatch on your lawn:

  • Watering the lawn too frequently
  • Infrequently mowing more than ⅓ of the grass blade
  • Applying too many lawn herbicides and fungicides

Benefits of Dethatching:

  • It allows the grassroots to access enough nutrients, air, and water
  • It can improve the health of the soil and the nutrient density
  • It exposes lower grass shoots to more sunlight
  • It improves the health of the grass and the curb appeal
  • It increases root strength
  • It reduces your lawn's susceptibility to various diseases and fungi
  • It increases its drought and heat tolerance
  • It helps winterize the lawn (spring growth prep)
  • It lessens the chances for mower scalping

When to Dethatch and Aerate

The right time to dethatch and aerate will ultimately depend on where you live and the type of grass you have on the lawn.

When to Dethatch

Ideally, dethatch during the growing season in your region to minimize potential stress on the lawn as much as possible.

  • Cool-season Grasses: Cool-season grasses commonly grown in the country's northern parts (such as Kentucky bluegrass and creeping red fescue) need to be dethatched during the early spring, late summer, or early fall seasons.
  • Warm-season Grasses: Meanwhile, warm-season grasses such as bermudagrass and Zoysia can be dethatched around the late spring to early summer months. These grass types are usually grown in the southern parts of the country.

Important Note: Avoid dethatching when the lawn enters dormancy or is facing heavy stress levels. Dethatching in the middle of the summer or during a drought may also severely damage your grass, so be careful!

How Often to Dethatch

In most cases, dethatching is only recommended by professionals if thatch takes over your lawn. If you're keeping a close eye on maintaining a thin, healthy thatch layer– that's fine. This will enable various nutrients to reach the soil and allow the grass to grow thick and healthy.

You may only need to dethatch the lawn once every few years, given proper lawn care activities. But, specific grass species such as bermudagrass, bentgrass, and Kentucky bluegrass are known to form thick thatch layers over time. These grasses will need routine dethatching at least once a year.

When to Aerate

Similar to dethatching, it would be best to conduct aeration during the growing season in your region. Doing so will ensure that your grass will quickly bounce back.

  • Cool-season Lawns: Fall is the best time to aerate your cool-season grasses since most weeds are not actively germinating around the time. They are less likely to sprout in the holes. But, it can also be aerated during either early spring or early fall.
  • Warm-season Lawns: It would be best to aerate in late spring or early summer to ensure quick grass recovery. Avoid aerating at the peak of the summer months as it may only leave behind lawn stress.

How Often to Aerate

Aerating is considered a preventative lawn maintenance activity. Hence, it's often done annually. Experts also recommend researching your soil type to determine the best routine for aerating your lawn per year.

Homeowners with sandy soil and few drainage issues will only need to aerate once every two to three years. Meanwhile, lawns with heavy clay soil and heavy foot traffic will need aeration every year (some will need as much as twice a year).

Frequently Asked Questions (FAQs)

Can I apply herbicide after aerating?

It depends on whether you intend to overseed or not. If you're not going to overseed, use a pre-emergent herbicide to keep crabgrass from growing in the holes. Hold off on a broad herbicide application if you want to overseed after aeration. Synthetic herbicides can damage new seeds and hinder the development of young grass; if weeds appear, spot spray to ensure a healthy lawn.

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

Before you dethatch or aerate your lawn, mow it. You'll want to cut it down to half (rather than one-third) of its original height.

How can I tell if my lawn needs aerating?

The soil beneath your lawn becomes compacted over time, and thatch builds up. It's time to aerate your property if it wasn't done last year. At the very least, you should aerate your lawn once a year. Most grass species thrive in the fall. Yards that are heavily used, especially those grown on thick clay or subsoil, may require more frequent aeration.

What time of the year do I need dethatching?

This is dependent on the weather, the soil condition, and the type of grass. Dethatching is often done in the springtime. Because you are removing mass from the soil, this step should be performed before any other treatments. Only when the dethatching procedure has been completed should you fertilize, lime, or overseed.

Kenneth Wilson
May 19, 2022
2terra, Yard & Garden

Kenneth Wilson

Retired contractor. Currently residing in Southwest Florida. Now in semi-retirement, I write and manage this blog focused on helping home owners make savvy decisions when it comes to finding contractors and getting their projects done. I also operate remodeling design service for homeowners.

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