Aeration of a lawn is the addition of air to the soil. Air is an important component of the soil and is essential to good plant growth. If the lawn is installed properly, the incorporation of coarse sand and organic matter into the soil promotes proper aeration. However, where traffic is heavy or the clay content is high, the soil may become compacted. The turf specialist can relieve the compaction by use of a powered aerator (Figure 13-12). There are several types of aerators and a range of sizes. All cut into the soil to a depth of about three inches and either remove plugs of soil or slice it into thin furrows. A topdressing of organic material is then applied to the lawn and a rotary power mower run over the organic material to blow it into the holes or slits left by the aerator. The plugs of soil left on top of the lawn may be removed by raking or, if not too compacted, broken apart and left as topdressing. Mechanical
equipment is made that can aerate and cover the topdressing in a single operation.