September is the beginning of our fall lawncare season. Overseeding or reseeding lawns can be done throughout the month and at the beginning of the month we can fertilize our lawns. Toward the end of the month, fall weed control can begin, but not until our temperatures cool off more. One of the other lawn activities that may be considered is lawn aeration.
Compacted soils can inhibit the growth of your grass. When a soil is compacted, the soil particles are packed too tightly together to allow oxygen and water to pass through the soil. This can lead to shallow roots for the grass plants and in turn, can lead to less drought tolerance. Compacted soils can also lead to more thatch build up on the soil surface.
Thatch is the accumulation of dead grass stems that don’t become decomposed. In compacted soils, earthworm activity decreases, as does the activity of other decomposing organisms. The reduction in decomposing organisms leads to the build-up of thatch which can cause problems with the growth of the lawn. Lawns with a high thatch layer can begin to die because the thatch layer repels water keeping it away from the roots of the grass plants.
One of the best ways to reduce thatch and alleviate soil compaction would be to aerate the lawn. Many people interchange the terms “power raking” and “core aerating” when it comes to lawn aeration. However, these are 2 very different activities. Power raking is a more intense form of reducing the thatch layer on the lawn. It is only recommended when a thatch layer is more than ½ inch because at that point it would be necessary to renovate a lawn rather than just to core aerate.
Core aeration is the method of aerating your lawn most recommended. This is the method where a machine is driven over the lawn while it pulls out many small, core soil samples throughout the lawn. These cores are laid over the top of the lawn but help by leaving holes in the soil surface for water and air to move in and they will fill back in. Core aeration will also sever the roots of the grass plants which stimulates the plants to grow new shoots to fill in the holes.
It is best to aerate a lawn in the spring or in the fall. This time of year is best because the plants can recover before winter or summer conditions that are sometimes difficult on our plants. It is also a good time of year to aerate due to the fact that the soil has more moisture in it than in the other dry months of the year. It is not recommended to aerate a lawn when it is too dry or too wet because it is more difficult to get the tines into the soil which can damage the plants more. It is not necessary to aerate your lawn every year, or sometimes at all. If your thatch layer starts to build up, you drive on the lawn a lot causing more compaction, or if the lawn begins to look thin, aeration can be done. At most, it would only be recommended to aerate a lawn every 3-5 years.