How Often Should You Aerate Your Lawn in Illinois? The Complete Seasonal Breakdown

Aeration is the one service almost every homeowner knows they should do, but nobody really knows when to do it. In Illinois, timing matters more than anything because our cool-season grasses respond best during specific windows of the year.

So here is the simple answer:
In Chicagoland, aeration should be done once a year in the fall and optionally again in spring if your soil is heavily compacted.

Let us break it down.

Why do lawns here need regular aeration

Illinois soil is heavy, compact, and full of clay. That means:
• Water sits on top of the lawn instead of soaking in
• Roots struggle to grow deeply
• Grass thins out from lack of oxygen
• Heavy foot traffic areas turn hard like concrete

Core aeration punches thousands of small holes into the soil so air, water, and nutrients can finally reach the root zone.

The best time of year to aerate in Illinois

Fall (the ideal window)

This is when cool-season grasses do most of their root growth. Aeration lets those roots expand quickly, and pairing it with overseeding fills in thin areas before winter.

Spring (secondary option)

If your lawn has severe compaction or winter damage, spring aeration can help jump-start recovery. It is not as ideal as fall, but still very effective when needed.

How to know your lawn needs aeration now

• Water runs off instead of soaking in
• The soil feels hard even after rain
• Thin patches or bare spots appear
• Heavy foot traffic creates visible paths
• Your lawn never looks as green as your neighbors

If any of these apply, your lawn is suffocating and aeration will make a huge difference.

Pair aeration with overseeding

This is the real magic. Aeration opens the soil, and the seed drops into those holes, creating a thicker, healthier lawn in the months that follow.

Want the best results this year? Ask about GroGreen’s Aeration and Overseeding program.