When soil becomes too compact it creates a surface barrier that prevents water, vital nutrients, such as nitrogen, potassium and phosphorus, and oxygen from getting to the plants’ roots. This compaction hampers the grass’ ability to create a healthy root system. The process of core aerating consists of using a machine appropriately titled an “aerator” to extract small plugs of dirt from the lawn and exposing the plants’ roots to air, water and nutrients.
Soil becomes compacted due to heavy foot traffic from humans and animals. No one step is going to do great damage to your lawn, but the sum total of activity creates pressure on the ground. A common misconception is that homeowners can use footwear with spikes to do the job, but this act just creates holes in the lawn while possibly compacting it further.
The common rule of thumb is to aerate your lawn at least once per year. If you have a newly constructed home, it is recommended to go ahead and aerate your lawn right away. The building crews during the construction of the home have been trampling and driving heavy machinery over the dirt, all while unwittingly compacting the soil.
When you decide to aerate your lawn it is best to do it with wet soil. The day after a heavy rain is ideal, but the day after you water the grass will work as well. You’ll want to make multiple passes with the aeration machine to ensure that the soil is properly loosened. You can also ignore the areas of your lawn where the soil isn’t compacted.
The soil plugs that you just removed from the turf should be allowed to sit out and dry up in the sun. Once the plugs are dry you should either use the back of a rake to break them up or pass over them with a lawn mower so that your lawn is uniform once again. Following the aeration process, continue to water, mow and fertilize your yard as part of a regular lawn maintenance program.
Check out our 'Quick Guide to Core Aeration' for more details.