Soil Aeration Methods: How To Improve Porosity In Your Lawn

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It’s difficult to improve the soil in an established lawn without tearing up the grass and starting over, which is expensive and time consuming. Most homeowners and lawn maintenance professionals choose to aerate the lawn, which helps improve compaction and increases oxygen absorption.

There are three basic methods you can use to aerate your lawn:

• Spike aeration- pokes holes in the turf
• Plug aeration- removes cores of soil
• Liquid aeration- encourages microbial activity to break down thatch

Each aeration method is effective under the right circumstances, but plug aeration is the most common and produces the fastest results.

The goal when you aerate your lawn is to introduce oxygen into the topsoil to encourage healthy root growth and microbial activity. This helps keep the soil soft, spongey, and able to drain freely.

So, which method is right for your lawn?

Let’s find out.

Spike Aeration Method

Spike aeration is a less invasive method of introducing oxygen into the soil, which makes it suitable for sandy or loose soils.

There are many tools you can use for this method (links to Amazon):

• Aeration shoes– a spike-covered sole that straps onto a boot and aerates the soil as you walk.
• Aeration prongs– a tool that looks like a pitchfork with spikes on the end.
• Spike roller– a tool that looks like a rolling pin studded with spikes and attached to a handle.
• Mower attachments– spiked tools that roll behind mowers.

Shoes and prongs are best for small spaces where it may be difficult to navigate a mower attachment or roller. However, it is not an efficient method for large areas.

These tools are also very physically demanding, and they are best used on softer soils to prepare them for light compost applications or overseeding.

Manual rollers are more heavy-duty and may be able to handle tougher soils, but they are still best for loose, sandy soils and preparing lawns for overseeding.

Mower attachments are capable of aerating large lawns without much physical effort, so these are a great option for homeowners with looser soils.

You may also use a mower attachment periodically throughout the summer to help improve clay or compacted soils, along with core aeration in the spring and fall. Intermittent spike aeration may help improve the infiltration rate during irrigation.

Spike aeration is simple; walk, push, roll, or pull your selected tool over the lawn until you have covered the entire area.

Aeration is usually reserved for the spring and fall, but spike aeration is much less invasive, so you can use them throughout the growing season as long as you irrigate well afterward and your lawn is continuing to improve.

Spike aeration should not be used on clay soils. When spikes push into clay, the clay compacts to fit the shape of the spike, and the clay loses porosity.

Core Aeration Method

This is the most common and most effective method for aerating compacted clay soils.

Core aeration removes cores of soil and leaves holes in the lawn, which helps incorporate oxygen and compost into the topsoil.

Core aeration looks ugly, but it provides the most immediate benefit to compacted lawns, and it helps to increase organic matter, which provides long-term solutions for clay soils.

There are two different tools you can use for core aeration (links to Amazon):

• Manual core aerator– a tool similar to a pitchfork that removes soil cores.
• Mower attachment– a rolling attachment that pulls cores from the soil.

A manual aerator obviously requires more physical labor and time, and it should be reserved for small, inaccessible spaces.

Mower attachments are the most common tool for core aeration, and these are the tools you will be able to rent from hardware stores. You can find aerators that have adjustable spacing as well as core sizes.

See our review of the best pull-behind core aerator lawn mower attachments.

There is, of course, one other option. That is to rent or buy a dedicated gas-powered core aerator. Those can be pricey though so before doing that be sure to read Should You Rent Or Buy A Lawn Aerator? 5 Key Considerations

The closer the spacing and the larger the cores, the more oxygen and compost you can incorporate into the soil. However, you must gauge how well your lawn will handle the aerator’s settings based on the growth habit of the grass.

Warm-season grasses tend to be shorter, break dormancy later, and have a creeping growth habit. These grasses are able to handle more extreme settings on an aerator because they can recover and spread quickly.

Cool-season grasses are taller, deeper green, and come out of dormancy earlier. They have a bunching growth habit and spread very slowly. These grasses cannot handle extreme core removal, so you must use a setting that is more spread out and not as wide in diameter.

Both warm-season and cool-season grasses can handle deep core removal. In fact, the deeper the better, regardless of turf species.

Aerate in the spring and/or fall when the grass is still actively growing. Avoid aerating during the summer to prevent drought stress. Topdress with ½” of compost after aerating to improve overall soil quality.

For more information, read Does Lawn Aeration Really Work? Side By Side Comparison.

Liquid Aeration Methods

Liquid aeration is not as common as manual aeration. It is an effective aeration method, but it serves a slightly different purpose than spike or core aerating.

Liquid aeration has two parts:

1.     Wetting Agent

The wetting agent penetrates deep into the soil, which helps improve water infiltration during irrigation. This also improves the environment in the subsoil and encourages insects and bacteria to dig deeper into the soil, which increases aeration and improves porosity.

Once water can consistently move deeper into the soil, nutrients and minerals are able to move and become available to root systems.

2.     Food for Bacteria

The majority of a liquid aerator is a surfactant, or wetting agent. This helps the product soak deep into the soil, which makes it easier for water to penetrate into the soil.

The remaining ingredients in a liquid aerator are different types of food for microbes to encourage biological activity deeper in the soil. This is usually some version of a seaweed extract.

Increased moisture and biological activity in the subsoil will increase nutrient availability and earthworm activity, which will help promote natural aeration and encourage a deeper, healthier root zone.

The big question, though, is do liquid aerators work?

Most lawn maintenance companies see them as a good way to keep pickier clients from complaining about cores spread out over the lawn.

Liquid aerators leave no mess, so customers don’t have to deal with a few days of soil cores spread over the lawn.

In short, yes, liquid aerators work. However, core aerators work better.

If you have to choose between no aeration and liquid aeration, choose the liquid. It will kickstart a chain reaction that increases natural aeration.

The better option, though, is to use both. Liquid aerators can help rain and irrigation water to penetrate deeper into the soil.

If you use a liquid aeration a week before core aeration, you can ensure the soil is soft enough to get the most out of your core aerator, and the bacteria in the subsoil will be primed to start incorporating a compost topdressing into the deeper layers of the root zone.

Use liquid aerators while the lawn is actively growing, and use them a week before core aeration in extremely compacted lawns.

Learn more about liquid aeration. Read Does Liquid Soil Conditioner Work? The Easy Aeration Promise.

Aerating is one of the most important maintenance tasks for a healthy, thriving yard. If you’re not sure which method is right for you, remember: any aeration is better than none. Just go for it.

Learn more about lawn care by reading Thriving Yard’s articles on preparing clay soil, in-ground composting, and how to amend clay soil without digging.