Yard and Garden: Properly Aerating Lawns

August 12, 2015, 3:24 pm | Richard Jauron, Greg Wallace

AMES, Iowa – Aeration is an important part of lawn care, but take care to aerate properly and at the correct time of the year. Here are some tips from Iowa State University Extension and Outreach horticulturists on the proper way to aerate a yard. 

What are the benefits of aerating the lawn?

Lawn PhotoAeration relieves soil compaction, improves water and nutrient movement in the soil, and prevents thatch accumulation. Aeration improves the growing conditions for the turfgrass plants and results in a healthier, more vigorous lawn.

When is the best time to aerate a lawn?

In Iowa, September and April are the best times to aerate Kentucky bluegrass and other cool-season lawns. While the overall results are beneficial, core aeration causes some initial damage. Aerating in September or April allows the grass to quickly recover during the favorable growing conditions in spring and early fall.

What is the proper way to aerate a lawn?

Aerate lawns with a core aerator. Core aerators have hollow metal tubes or tines that remove plugs of soil. Avoid spike-type devices that simply punch holes (compacting the soil) in the ground. Core aerators are often available at rental agencies. If you prefer not to do it yourself, core aeration is a service provided by many lawn care companies.  
Remove soil cores that are approximately three-fourths of an inch in diameter and three inches long. For best results, aerate lawns when the soil is moist. Avoid aeration when soils are dry or wet. The tubes or tines will not be able to penetrate deeply when the soil is dry and may get plugged with soil when the soil is wet. Lawns that are properly aerated should have 20 to 40 holes per square foot. Since most core aerators won’t remove the proper number of holes with a single pass, several passes are usually necessary.

How often should I aerate a lawn?

The frequency of aeration is largely determined by the soil type and the amount of use. Lawns growing in heavy, clay soils and those subject to heavy foot traffic should be aerated twice a year. Once a year should be sufficient for lawns that are established on well-drained soils and experience little traffic.  

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