How to Aerate Your Lawn (and When to Do It for Best Results)

By using a core aerator to remove small plugs of soil, you’ll loosen compacted earth, break up thatch, and give your lawn the breath of fresh air it needs to thrive. It’s a straightforward weekend project that can lead to greener, healthier grass.

What is Lawn Aeration?

Even though plant roots are underground, they still need oxygen. In a sense, the roots “breathe” (a process called cellular respiration), and without oxygen, the plant may perish. They obtain this oxygen from the atmosphere, and if they can’t get enough, they begin to struggle. You sometimes see this in action when a houseplant is overwatered in its container—the plant starts to wilt and look sickly due to a lack of free oxygen.

Aside from overwatering, a plant can also be deprived of oxygen if the soil around it is overly compressed. It’s easy to see why; normal soil isn’t solid and has plenty of cracks, crannies, and air pockets that let the atmosphere in. But when soil has a lot of foot traffic, dogs running around, kids playing on it, or tire compaction occurs from lawn mowers or other vehicles, the soil compresses and oxygen struggles to penetrate.

And what soil is most likely to suffer from this? The soil in your lawn of course! Your lawn is the center of backyard fun, but it pays the price in soil compaction. And it’s not only a lack of oxygen that’s a problem—compacted soil prevents water and nutrients from settling into the lawn properly.

There’s also the issue of thatch. You know that when you see it—those tufts of faded, dead grass blades that build up on the ground under your live lawn. Thatch is essentially a thick layer of dried roots, stems, and leaves. Some thatch buildup is just fine, but the University of Wisconsin Extension says once it reaches an inch or more in depth, it can become unsightly, unhealthy for the lawn, and can contribute to issues with powdery mildew.

Proper lawn aeration can help alleviate these issues. It may not be the complete answer, but it can definitely be part of the solution. 

When to Aerate Your Lawn

Timing matters when it comes to aeration. The ideal time for soil aeration depends on your location, but Iowa State University says that lawns with cool-season grasses should be aerated in spring or fall. Avoid aerating in summer when lawns are already stressed. Aerate warm-season varieties from late spring through early summer. Aerating when your grass is growing helps it recover quickly and fill in the holes left behind. Avoid aerating during extreme heat or dormancy, as it can stress your lawn rather than help it.

Once a year is usually sufficient for soil aeration; maybe twice a year if you have clay soil or your lawn receives unusually heavy foot traffic. Some lawns and grass types do well with less frequent aeration—every two years or so. But if you haven’t done it in several years, it might be time to give your lawn a helping hand now. 

Signs That Your Lawn Needs to Be Aerated

Before you begin, make sure your soil actually needs aeration.Nobody wants to spend time and money needlessly. So, how can you tell if you even need to aerate your lawn? Here are some signs to watch for:

• Pooling and puddles.  If water pools on the surface or your lawn feels spongy or hard, it’s probably time. Have you noticed if water that once drained away easily now puddles and pools after a heavy rain? If water lingers where it shouldn’t, especially in a new place, it’s a good indication that the soil is more compacted than it once was. Aeration can help the water seep into the ground properly.
• Dead grass. Thinned out patches, yellow grass—it’s easy to tell when your lawn is looking sickly. If these signs are occurring, it’s possible that a lack of aeration is playing a role.
• Visible traffic patterns. It’s wise to try to avoid packing down the same route time after time, but hey, life happens. It’s easy to see when traffic has compacted the soil, but don’t worry: aeration can help restore it.
• Abundant thatch. Some thatch is natural and can even protect the lawn during the winter, but too much of a good thing is detrimental, and aeration can help break this up, too.
   

How to Aerate Your Lawn

1. Choose your tool. 

A core aerator is the most effective option—it pulls out plugs of soil and thatch, unlike spike aerators, which can compact the soil further. You can rent one from a garden center or equipment rental store. You can try to aerate with a hand tool (which looks like a small pitchfork with an aerator on each tine), but this is arduous and time-consuming.

• Mechanical aerator can range from hand-push models (looks kind of like a grass seeder), to motorized self-propelled walk-behind aerators, to towable aerators that pull behind your garden tractor (ideal for large properties). Usually, multiple corers are on spinning spools that dig in and quickly core the lawn and leave the plugs behind as the machine rolls. 

You can hire a lawn service to aerate your lawn or do it yourself. It might not be worthwhile to purchase a mechanical core aerator only to use it once a year, but you can rent them easily.

Note: There are also “spike”-style aerators that just poke a hole in the ground, but don’t pull out a core plug. Generally, these are not considered as effective, and may even increase soil compaction.

2.  Prepare your lawn.

Mow and water your lawn a day or two before you aerate it. Avoid watering on the day you aerate, and you may want to wait if it’s just rained. , and water it lightly if the soil is dry. Moist (but not soggy) soil is easiest to aerate. 

3. Aerate in multiple directions.

Run the aerator over your lawn in one direction, then repeat at a perpendicular angle. This helps ensure even coverage.

4. Leave the plugs.

Let the soil plugs break down naturally—they’ll return nutrients to the soil and improve structure over time.

5. Follow up with care.

After aerating, it’s a great time to overseed, fertilize, or top-dress with compost. Your lawn will be better able to absorb everything you add. Learn more about when to seed a lawn.

Picture of a grass aerator on the green lawn image widget. Press Enter to type after or press Shift + Enter to type before the widget

What to Do After Aerating Your Lawn

You might be tempted to rake up the core plugs the aerator tosses. This isn’t necessary and can actually be detrimental. The plugs contain good organic material and will break down after a good watering or rain.

Post-aerating is a good time to do any other lawn maintenance you were planning, like reseeding and fertilizing. Water well, too. All of these tasks should be even more beneficial with a lawn prepared to accept nutrients more easily.

Bottom line: Aerating your lawn can benefit your lawn’s overall health, and it’s a relatively easy project that you can do with your own or rented equipment. You’ll help ensure your lawn’s continued success for years to come!