We often overlook problems associated with soil compaction. Insects, diseases, nematodes, improper watering and a lack of fertilizer are often blamed for a lawns decline when the real culprit is compaction. The problem starts when the top 4 inches of the soil become compressed, impeding the movement of air, water and nutrients to the grass roots. This stresses the grass plants, making them less able to compete with weeds and slow to recuperate from injury. In time a compacted lawn needs renovation.
Compacted soil contributes to the accumulation of thatch because restricted oxygen levels in highly compacted soils impair the activity of earthworms and other thatch-decomposing organisms. Left unmanaged, thatch can lead to serious maintenance and pest problems. Thatch accumulates faster on compacted soils and heavy clay soils than on well-aerified soils. Therefore, some lawns may require frequent aerification to aid in thatch control.
If soil is compacted, the solution is straightforward: aerify. The practice of physically removing cores of soil and leaving holes or cavities in the lawn is defined as core aeration or aerification.