Mechanical aeration provides an excellent, and probably the only, means of correcting or alleviating soil compaction which may be quite serious on many lawn areas. Compaction occurs primarily in the surface area of the lawn. A compacted layer as thin as ¼ to ½ inch can greatly impede water infiltration, nutrient penetration, and gaseous exchange between the soil and the atmosphere. Compaction of this type in the surface layer of soil can be corrected or reduced by the use of suitable aerating equipment.
Aerating machines remove plugs of soil from the turf area, thereby creating an artificial system of large or noncapillary pores by which moisture and plant nutrients can be taken into the soil. They also provide a breathing system through which carbon dioxide can escape from the soil and oxygen can enter the soil. A rapid intake in movement of water and air is recognized as a prime necessity in correcting damages to the turf caused by compacted soils.
Spring and early fall are the best times to aerate.