Core aeration opens the thatch layer and improves water infiltration into the root zone. the timing of this task is important.
Spring is the best time for worm season grasses. Aerate cool season grasses in late Summer or early Fall. this simple process also improves the oxygen level to the roots.
The holes eventually fill in and grow over, but the permeability of the soil remains vastly improved. Coring aids root growth and is particularly helpful on lawns with heavy foot traffic. It’s also considerably easier on the lawn than power raking.