Lawn Aeration: What It Is, When to do it and Why It Helps

Basic lawn care including mowing, fertilizing, and watering goes a long way towards creating a beautiful and welcoming lawn.

Yet many lawns, especially those with clay soil or heavy foot traffic, require more than just the basics. These lawns require aeration to help move air, nutrients, and water beneath built-up grass to your lawn’s roots.

If your lawn is looking less than stellar or you’ve noticed excess water building on top of the soil, then lawn aeration might just be the key to your landscaping woes.

Here’s everything you need to know about how to aerate your lawn and why it’s so important to the health and beauty of your grass.

What is Lawn Aeration?

Lawn aeration is simple. It's the process of air moving between the soil and the rest of the atmosphere.

In this way, aeration is a naturally occurring process. Air is always moving between the soil and the atmosphere, no matter the health of your grass.

The problem is that soil compaction and buildup of grass thatch over time make it difficult for this air to reach the soil and the roots it contains.

That’s where manual lawn aeration, also known as core aeration, comes into the picture. It’s the process of manually aerating a lawn by creating small holes throughout it.

Seattle Public Utilities states that these small holes then allow air as well as nutrients and water to penetrate the grass and soil to arrive more successfully at the grass roots.

The result of this is pretty obvious: healthier grass roots which equal healthier grass which equals a much better-looking, more impressive lawn.​

Why Aerate Your Lawn?​

​The benefits of lawn aeration include:

  • Improved air flow to soil
  • Improved water flow to soil
  • Improved fertilizer flow to soil
  • Stronger, healthier grass roots
  • Softer, more cushiony grass
  • Improve lawn resiliency (better heat/drought tolerance)
  • Less soil compaction
  • Reduced water runoff
Effects of Lawn Aeration

Courtesy of

Out of all these benefits, Penn State College of Agricultural Science states that the main goal of lawn aeration is to enhance root growth for stronger, healthier grass. Enabling air, water, and fertilizer to more easily flow into the soil does just that.

Though lawn aeration benefits almost all lawns, it’s particularly effective for those that:

  • Are mostly clay soil
  • Receive heavy foot or vehicle traffic
  • Dry out quickly and becomes spongy
  • Were created with sod
  • Water is puddling
  • Were built as part of a new home construction

If your yard meets any of these marks, then lawn aeration is likely a smart idea to consider.

​If you plan on overseeding, aerating your lawn first is a smart move because it will open the soil and promote more seed to soil contact and, in turn, stimulate better growth. Overseeding prior to aerating will be less effective because the seed will not disperse correctly.

How to Aerate a Lawn​

​Here’s how to aerate a lawn:

  • Prepare lawn one day in advance by ensuring the soil is most
  • Make passes with aerator machine over the lawn, so the entire affected surface receives aeration.
  • Wait for soil plugs to dry before breaking them down with the back of a rake. Or you could just leave them and let them break down naturally.
  • Fertilize and overseed.

As you can see, aerating a lawn yourself is easy. All it takes is renting or buying an aeration machine and running it over your yard as directed.

​Follow the machine’s manufacturer directions to a T. Note that most machines only aerate a small portion of your yard at once. For this reason, several passes are required.

​According to Clemson Cooperative Extension, follow these steps on how to aerate a lawn, and you'll be well on your way to achieving the healthy and pristine lawn of your dreams.

​But how do you actually know if your lawn needs aeration? You don’t want to waste the money, time, or effort unless the process is necessary.

​In addition to keeping your eye out for noticeably compacted soil, puddling water, and buildup of thatched grass, you can use a simple test to see if aeration is needed:

  • Push a screwdriver into the soil.
  • If it’s difficult to push in, aeration is likely needed.
  • Verify by digging up a one-foot by one-foot by one-foot area of lawn with a shovel.
  • Look at the roots of the grass you just dug up.
  • Roots between 4 to 6 inches deep are healthy.
  • Roots shorter than 4 inches, especially those between 1 and 2 inches, need aeration.

Now that you’ve correctly aerated your lawn, it will be primed and ready to be fertilized and overseeded. The overseeding process will be much more effective if the lawn is properly aerated beforehand.

Lawn Aeration Tools​

​The effectiveness of lawn aeration relies heavily on the specific type of machine you use.

​Many types of lawn aeration tools and equipment are available. The two most common (and most effective) are plug aerators and spike aerators.

​Plug aerators dig into the soil, removing a small plug of grass and soil. It then deposits the plugs onto the surface of your lawn.

​A spike aerator, on the other hand, simply pokes small holes into the ground. These machines don't remove any dirt or grass.

​Both types of machines have their benefits. However, most people will benefit most from a plug aerator claims Landscaping Network.

​A plug aerator is much more effective than a spike aerator. It more greatly enhances air flow to your grass, roots, and soil.

​Spike aerators should also be avoided because low-quality versions can actually increase soil compaction due to the poking motion.

​Another factor to look at is how far apart each aerator spike/plug is located. The best plug aerators remove plugs between 2 and 3 inches apart from each other.

​These plugs should be approximately 2 to 3 inches deep. The best machines remove plugs around 0.5 inches in diameter.

​Insider Tip: Aerators can be expensive to rent – consider splitting the expense with a neighbor whose lawn also requires aerating.

W​hen to Aerate a Lawn

​Aeration isn’t just something you should do to your lawn on a whim. Certain times of the year, particularly the growing season, are best for aeration.

According to University of Illinois College of Agricultural, Consumer, and Environmental Sciences, the growing season is the best time for aeration because the lawn treatment can actually slightly damage your grass. This is all part of the process. Aerating during growing season enables this grass to heal and grow back more quickly.​

Cool season grasses are best aerated during spring or fall. Warm season grasses are best aerated in late spring to early summer.

​Most lawns only require aeration once a year. This is true for almost all home residences.

​Certain lawns, particularly school lawns and others with heavy foot traffic, might require aeration two times a year.

​Golf courses, sporting fields, and public parks require the most aeration. These lawns sometimes need to be aerated as many as three to five times a year.

​Final Thoughts

Soil compaction is one of the most overlooked landscaping problems homeowners face.

​Even if you mow, water, and fertilize properly, improper aeration can lead to a lackluster looking yard.

Make sure air, nutrients, and water reach your lawn’s roots with proper aeration. Practice this treatment technique once a year, or as needed, for the best results.

You’re sure to notice results within a week or two of aeration. The first sign will be the holes filling with new white roots. Soon the holes will fill in with new grass. Puddling of water shouldn't be an issue anymore.

Though lawn aeration can’t work miracles, it does make a huge improvement to your yard when combined with other basic lawn care techniques.