Do You Really Need to Aerate Your Lawn in the Fall?

Aeration is touted as important, but the chore is routinely ignored, especially by homeowners with large lawns. In fact, our own group of friends questioned me to learn if it was truly necessary.

The short answer is yes—sorry, guys—and it's especially important for some types of lawns.

Aeration not only helps your grass grow stronger roots, but it also prepares your lawn for better growth come spring.

What is Aeration and Why is It Important?

Aeration is the process of creating small holes in the soil to remedy soil compaction.

"Aeration creates channels for air, water, and nutrients to move deeper into the soil, promoting stronger root systems and overall healthier grass," highlighted Matthew Koch, Ph.D., Director of Biotechnology, Genetics, and Seed at Scotts.

Over time, soil in an otherwise healthy lawn can become dense and compacted, which prevents the soil from "breathing." When the soil can't breathe, it means the nutrients have a hard time reaching the root zone. Aeration solves this by improving the soil structure.

Benefits of Aeration:

• Improves soil structure by breaking up compacted areas
• Improves nutrient uptake, which promotes deeper root growth
• Reduces water runoff by allowing better water infiltration
• Breaks down thatch buildup to prevent fungal growth and improve lawn health

Fall vs. Spring Aeration

"Fall aeration is ideal for cool-season lawns because it allows the grass to recover and strengthen before winter," shared Koch. If you have cool-season grasses like Kentucky bluegrass, fescue, or ryegrass, fall is the best time to aerate.

For warm-season grasses such as Bermuda or Zoysia, the best time to aerate is late spring or early summer... but you can still aerate in early fall if done soon enough to allow for recovery before temperatures drop.

Regional Considerations

• Northern US (Cool, Wet Climates): Fall is the ideal time to aerate before the first frost. Get it done before your grass is in its dormant winter period.
• Southern US (Warm, Arid Climates): Aerate in early fall or late spring for best results, especially in regions where compacted soil from dry weather conditions is common.

Spike Aeration vs. Core Aeration

There are two main methods of lawn aeration: spike aeration and plug (core) aeration.

"Plug aeration is generally recommended because it removes soil cores, which opens up more space for air, water, and nutrients to reach the grass roots," explains Koch.

Spike aeration, on the other hand, can sometimes make compaction worse by pressing the soil down around the holes.

While lawn care experts note that both methods alleviate compaction, soil plug aeration is often more effective (especially in heavy clay soil). Why? Simply because the plugs of soil open more space in the soil surface for air and nutrients.

Which Method Should You Choose?

• Spike aeration: Easier and more accessible for small or slightly compacted lawns. 
• Plug aeration: Core aerators help heavily compacted soil or thatch build-up. It has longer-lasting benefits for lawn owners.

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How to Aerate Your Lawn in Four Steps

If you’re new to aerating, don’t worry—it’s not as complicated as it might seem. You can rent a powered aerator machine, or do it the old school way with garden forks.

Depending on the size of your lawn it may be an all-day or all weekend project, but you'll be happy come spring when you walk through your healthier lawn. 

1. Water your lawn one or two days before aerating to soften the soil. This is especially important in areas with heavy foot traffic!
2. Aerate the lawn using a plug or spike aerator, going over the entire lawn in a pattern that covers all areas. Put on a podcast, carve out time in your day.
3. Apply fertilizer immediately after aeration to feed the roots as they absorb water and nutrients more efficiently.
4. Water the lawn again to help the soil settle and allow the nutrients to penetrate deeply into the aerification holes.

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Should You Also Overseed Your Lawn in the Fall?

If you’re already aerating and the soil temperatures are favorable, yes, overseed your lawn.

"Aeration with overseeding also helps the grass seeds penetrate deeper into the soil, which can significantly improve germination rates," notes Koch.

• Thickens your lawn and reduces bare spots
• Improves the grass variety by introducing new, more resilient grass types
• Enhances overall lawn health by reducing the risk of weeds

For best results, overseed immediately after aerating, followed by a deep watering.

If you saw our article on how to plant grass seed in the fall, you'll know that the seed needs time to establish itself into healthy grass before winter.

Can You Make Any Mistakes While Aerating?

• Not watering beforehand: Aerating dry spots is much harder (and less effective). Water your lawn a day or two before aerating to soften the grass and underlying dirt.
• Skipping fertilization: "After aeration, it’s essential to follow up with a good fertilizer like Scotts® Turf Builder® Lawn Food," suggests Koch. Access to fertilizer helps the grass roots when they need it the most—right after the aerator machine creates holes where the fertilizer can settle.
• Aerating at the wrong time: Seasonal weather's a factor. Aerating too late in the season can prevent an otherwise healthy lawn from recovering before winter. Aim for early to mid-fall for cool-season grasses and early fall or late spring for warm-season grasses.