Compaction is when soil is packed down. Both lead to an unhealthy lawn. Thatch can build up over time in any lawn. It impedes water and air movement and is an ideal habitat for insect pests such as grubs seen to the right. Thatch can be controlled with equipment that aerates and dethatches turf.
Soil compaction restricts water movement, air movement and limits how deep grass roots can grow.
Soil compaction can be controlled by keeping foot and other traffic off the lawn when it is moist. Turf aerators are available at your local tool rental retailer. Full-service lawn care professionals offer aeration as a service too.