How and When to Aerate Your Lawn

Beautiful Home With Green Grass Yard
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A lush lawn and gorgeous garden complement a beautiful house.

If a house is like a lovely diamond gemstone in an engagement ring, then the yard is the elegant platinum setting in which it rests. The flowering bushes and trees are much like smaller gemstones enhancing the sparkler at the center, and a lush lawn is like the gold mounting, polished to perfection. Keeping a lawn looking its best requires maintenance. Mowing and watering are obvious. And you probably know about fertilizing. But were you aware a lawn needs aerating to keep it healthy and thriving?

Aeration involves removing small plugs of soil at regular intervals in the lawn. It reduces soil compaction—in which soil is tamped down—and allows water, air, and nutrients to flow down between the roots of the individual plant roots. This helps the roots grow more deeply and in turn reinvigorates the lawn grass.

When to Aerate

Some experts recommend aerating annually in the fall. Others say aerating isn't necessary if your lawn looks vigorous and strong, and recommend that it be done as infrequently as every three to five years.

When you do aerate, do it during the growing season for whatever type of grass you wish to promote in your yard—that way, lawn growth will actively fill the holes left during aeration. For warm-season grasses such as carpet grass, St. Augustine grass, and Bermuda grass, aerate in late spring. For cool-weather grasses such as Kentucky bluegrass and tall fescue, aerate in the early fall. Always aerate in mild temperatures to reduce stress on the grass, and never aerate in the summer, when many grasses are semi-dormant but the weed crabgrass is flourishing.

Lawn closeup.
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Aerating allows water, air, and nutrients to flow down between the roots to reinvigorates grass.

Different soils have different aeration needs. Clay-rich soils, for example, naturally have more compaction and need more frequent aeration. Assess soil compaction by pushing a screwdriver or pencil into the ground. You'll find this challenging if the soil is compacted. To confirm your findings, test with a shovel. If it sinks easily to a depth of half the blade, the soil isn't compacted. But if you're struggling to push in the shovel, maybe even jumping on it, it's a sign that you need to aerate.

It's a good idea to aerate if any of the following apply to your lawn:

  • The grass dries out quickly and feels spongy. This indicates that the lawn has a thatch problem. Thatch is a loose layer of blended dead and living blades and roots lying between the grass and the top of the soil. It builds up when turf produces waste more quickly than the soil organisms can break it down. In this case, aeration improves airflow through the soil, improving microbial activity and breakdown of thatch.
  • The yard sees a lot of activity that packs down the soil, such as kids playing in the grass, pets racing back and forth on it, and heavy foot traffic. When the ground feels hard as a rock even if there has been adequate moisture, it needs aerating.
  • The lawn takes a long time to drain, with large puddles left behind for a period of time after it rains. In this case, it definitely needs aerating.
  • The grass looks patchy and thin, turns brown during heat spells, and stops growing in the August swelter. It's a good candidate for aerating.
  • If you know you have a heavy clay soil, aerate annually.
Manual core aerator manufactured by Corona
credit: Lowes
A manual core aerator

Equipment for Aerating

Which type of aerator to use depends on the size of your lawn or the area that needs attention.

  • A manual core aerator looks something like a pogo stick. Many different manufacturers produce these tools; they cost roughly $25 to $80. You won't aerate a lawn quickly with this kind of tool, but it works well for little yards or small problematic patches.
  • Self-propelled aerators look like a three-wheeled gas mower on steroids. With one of these, you can aerate your yard much faster than with the manual kind. Buying one of these will put you out several thousand dollars, so they are normally rented.
  • Towable plug aerators make short work of wide expanses of lawn. One of these only costs a few hundred dollars, but you have to own a riding mower to hitch it to.

You can rent both self-propelled and towable aerators from home improvement stores. If you don't want to do the aerating yourself, hire a lawn care company or landscaper to do it.

Self-propelled core aerator manufactured by Classen.
credit: Home Depot
A self-propelled core aerator.

Tips

Poking holes in a lawn with a spike isn't the same as aerating. A piece of equipment with solid tines merely pokes holes without removing plugs of dirt from the ground. This isn't effective, because it actually compacts the soil around the hole. There are three kinds of spike aerators: one that looks like a modified pitchfork; another that looks like a manual push mower, but with spikes instead of blades; and a kind that mounts to your shoes, something like cleats. Don't get a true plug or core aerator confused with one of these spike aerators.

How to Aerate a Lawn With a Manual Aerator

Before you begin, stick a trowel into the lawn, remove it, and look at the tool. Aerating is easier when the soil is moderately moist. If the trowel has a lot of dirt sticking to it, the ground is too wet to aerate.

  1. First, water the lawn to soften the ground. Aeration will be easiest if the ground is moist, though not soggy.
  2. Place the tool on the ground with the prongs or tips facing down. Place your foot on the foot bar and push down fully into the earth.
  3. Grasp the handle and pull the tool back out. Round plugs of soil with tufts of grass will be removed by the hollow prongs on the tool.
  4. Repeat every 6 to 12 inches to aerate the desired area—either the entire lawn or just affected areas. You will notice that with each subsequent step, the previous plugs will be ejected from the tops of the prongs. There is no harm to leaving these plugs lying on the ground—they will break down on their own. Or, you can rake them up once the aeration is completed.
Spike aerator manufactured by Yarn Butler.
credit: Lawn Butler
A spike aerator. This tool isn't as effective as a core aerator.

Tips

If you're renting an aerator, you probably won't need it for the entire rental period, so consider going in with a neighbor to share the costs.

Using a Self-Propelled Aerator

This machinery operates much like a lawnmower, but it is powerful, so you really need to hang on to it! Make sure you get instructions on its use from the rental center where you lease it.

These machines are generally gas-powered, with engines that are started by a pull-crank or sometimes an electric starter. Engaging the clutch starts the machine's wheels turning and the drum working to dig out cores of soil and grass. Make two passes over the entire lawn with the machine, the second at a 90-degree angle to the first.

When you're done, just leave the plugs that were pulled out on the lawn to slowly decompose and return their nutrients to the soil. You can speed up this process by mowing with a low-cutting blade after the plugs have dried. After mowing, water the lawn to dissolve the plugs still more.

Towable aerator.
credit: Home Depot
A towable core aerator.

Using a Towable Aerator

A towable aerator can be used if you own a riding lawnmower or small tractor, or can borrow or rent one. A towable aerator can also be leased at tool rental centers, but if you have a very large lawn, you may want to invest in owning one.

Begin by hooking up the aerator to your mower or small tractor. Tow it around the yard in the same manner as you would while mowing the yard. Make two passes, with the second pass made at a 90-degree angle to the first. As with other methods, the plugs can be left on the lawn to decompose.