When is the best time to aerate a lawn?

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Question When is the best time to aerate a lawn?

Answer Aeration is often misunderstood when it pertains to grass. In its most simplistic form, it is the process of introducing air (or oxygen) into the soil. In order to produce healthy plant roots, air and water are both necessary in the soil.

Compaction exists when the soil particles have been pressed together to eliminate the air space. This situation can be caused by pets, vehicles, lawn mowers or professional wrestlers practicing body slams. The rate and extent of compaction is determined by the type of soil, moisture level and frequency of activity.

Core aerators are used to alleviate soil compaction. These machines pull a core or plug of soil from the ground and drop it on top of the grass. Air, water and fertilizer can then enter the soil through the hole made by the aerator. A good aeration job should look like a giant pack of dogs made a pit stop in your yard. These soil plugs will dissolve after a couple of rain showers.

The plug of soil dropped on the grass will help with another potential problem – thatch. There are thousands of microbes in the soil that naturally break down the stems and roots which make up thatch. Placing the soil on top of the grass gives the microbes access to this food source.

Grass clippings do not cause thatch. They are broken down quickly by the soil microbes. Warm season grasses have the most thatch potential because they have more roots and stems above and below the soil line. Cool season grasses have less of a problem with thatch. However, cool season grasses like fescue usually grow better in soils that are more prone to compaction (clay soils).

Aerating a lawn is good for many reasons. On the other hand, the actual process causes some stress on the lawn. Grass roots are pruned and access to the soil is opened up for opportunistic weeds. Therefore, this process should be exercised when the grass is most competitive. Cool season grasses can be aerated in the fall (September-November) or spring (March-April) when they are actively growing. Warm season grasses can be aerated during the summer (late May through early August). Whenever possible, aerate before fertilizing or seeding.

Spiking is a form of aeration that uses solid tines like the spikes on a golf shoe. This type of aeration causes less injury to the turf, but it also causes more compaction and does nothing to alleviate thatch.

For more aerating info, visit http://www.oznet.ksu.edu/library/HORT2/MF2130.PDF

If you don’t have internet access, then call the Extension Office at 893-7533 or email me at gary_pierce@ncsu.edu

There is no research which shows the wearing of golf shoes has any positive effect on your lawn. However, this practice is guaranteed to make your pets and water hose very nervous.

Gary L. Pierce

Horticulture Extension Agent

Harnett County