Aeration & Dethatching

When to Aerate and Dethatch

• "Thatch" refers to mat of dead and live grass stems mixed with live roots. It occurs in all lawns and will look like a brown layer below the green of the lawn. A small, thin thatch layer can be beneficial in preventing disease and weed growth, but too much can increase the incidence of disease. The appearance of your lawn will also suffer. Aeration is the removal of small portions of lawn soil. These portions are known as plugs, and their removal improves the circulation of nutrients and loosens compacted soil. This allows the roots of your lawn to spread. You should definitely aerate if your grass roots do not extend down past the first inch or two of soil, or if you have a half-inch or more of thatch.

How to Dethatch

• Before beginning the dethatching process, mow your lawn more closely to the ground than usual. Next, if you're using a thatching rake, simply dig into the turf layer and drag in a raking motion until the majority of the thatch is removed. If you're using a motorized dethatcher, adjust the blades until they are slightly above the surface of the soil. Space them by at least 1 inch. Make your passes over the lawn oriented horizontally, and then make another pass oriented vertically along the lawn. When you're finished, you will still need to rake up the debris, but the process will not be nearly as laborious.

How to Aerate

• It is usually convenient to aerate after dethatching. Prepare for aeration by watering thoroughly at least 48 hours beforehand. Make sure you know the location of any underground structures to avoid damaging them during the aeration process. As with dethatching, aeration can be done by hand or with a motorized machine. Either way, you will be removing plugs of soil 1/2 to 3/4 inch wide. These plugs should be a minimum of 1 inch long, but no longer than 6 inches. Plug removal will typically be spaced 4 to 6 inches apart. Leave the plugs on the grass surface, as over time they will be reincorporated into the earth.

Tools Recommended for Aeration and Dethatching

• The thatching rake and hand aerator are the tools needed to do these lawn care tasks manually. The downside is that aerating and dethatching by hand is slow and tiring. There are two types of motorized aerator. The roller aerator consists of a rotating drum that has coring tines mounted to it and removes the plugs as the drum turns. This type occasionally causes unsightly tears in the lawn due to its method of plug removal. The piston aerator simply punches the cores from the lawn. It generally does not leave tears and is a slight upgrade over the roller aerator.