Aerating your lawn is one of the most important things you can do to keep your lawn healthy and attractive. According to the Lawn Institute, the aerification process reduces thatch build-up in your lawn and opens passageways for air, water and nutrients to reach grass roots. In drought conditions, aeration allows moisture to reach thirsty roots. During times of heavy rain, aeration allows air to penetrate the turf and dry up excess moisture before it becomes a source of disease.

The Best Time To Aerate Your Lawn

Cool season grass varieties like tall fescue and Kentucky bluegrass are best aerated during their peak growing season, which usually occurs in the early fall months. Homeowners with warm season grasses like bermuda and zoysia should wait until late spring or early summer to aerate their lawns.

How Lawn Aeration Is Done

Some lawn aerators use hollow tines to puncture the lawn, extracting small cores (typically 1/2 inch to 3/4 inch in diameter) of soil and depositing them on the lawn. Others use solid metal spikes to poke holes in the soil without removing plugs. While both methods can work, most experts agree that core aerators are best, because they're more effective at removing thatch build-up and are less likely to contribute to compaction.

Professional lawn care services will aerate your lawn for a fee, but many homeowners choose to do it themselves. Lawn aerators are available for purchase or rental through many gardening centers, home improvement stores and rental outlets. These are popular machines during peak growing seasons so plan in advance to make sure an aerator is available when you want it. They're also big and heavy; you may want to inquire about pick up and delivery services, and you may need to line up some helpers.

Depending on the condition of your lawn, one or two passes with a core aerator may be all that's needed. Extra passes may be required on older lawns or in heavy traffic areas. If you're planning to overseed-a good idea if the existing grass has thinned or is showing signs of stress-rake over the aerated lawn until core holes are 1/2 to 3/4 full before applying seed.

When you're done seeding, spread a starter-type fertilizer that is higher in phosphorus (P) and potassium (K) than nitrogen (N), then rake again to break up the remaining cores and spread soil over the seed. Water lightly and often to keep the new seed moist until it germinates and begins to grow.

Why Lawn Aeration Matters

It's estimated that more than two-thirds of residential lawns are currently growing on compacted soils. This may be the result of too much compaction or too little topsoil when the yard was first graded, but it can also result from heavy foot or vehicle traffic, long-term thatch build-up and high clay content in the soil.

Whatever its cause, compaction can reduce the amount of oxygen in the soil and prevent nutrients from reaching grass roots. Carbon dioxide builds up in the soil, stunting growth and thinning the turf. The result is a lawn that seems lethargic, with less density and less resistance to the temperature and moisture extremes that are often experienced during summer and winter months.

If you're not sure whether your lawn needs aerated, you can check by removing a small section of sod (approximately 1 foot square by 6 inches deep). Use your hand or a trowel to scrape soil from the underside of the sod until you expose roots. If grass roots only extend one or two inches into the soil, your soil is probably compacted and may benefit from aeration.