The major benefit of aeration is to loosen compacted soils. If the ground is not composed of clay soils, subjected to children or animals moving about or automobiles that may drive on it, the lawn may not require aeration. Ground subjected to winter freezing and thawing or that is home to a healthy earthworm population may remain open and not require aeration. Wet areas often become compacted and will need to be aerated. A simple inspection can determine if aeration is necessary. Soil that is subjected to heavy foot traffic should probably be aerated annually.
Aerating opens the soil by pulling out small plugs of soil about 3-5 inches deep and then depositing them on the surface to eventually decompose and disintegrate back into the ground. Make sure you leave them on the ground to decompose. This provides the opportunity for the grass root systems to acquire the nutrients, water and air that are essential for growth. Loose soils allow the roots systems to penetrate more deeply into the soil and become stronger and more resilient if they have to fight off the effects of drought or disease. Soil microorganisms become more abundant and help in breaking down and preventing the formation of thatch in the lawn. Aerating destroys heavy thatch in the coring process and aids in adding this nutrient rich compost back into the soil.
Aerating is an ecological friendly endeavor. Water is more readily absorbed by loose soils. Fertilizers which are subject to run off and contaminate adjoining water sources are less likely to run off because the loose soil more readily absorbs the nitrogen, phosphorus and potassium that is contained in the fertilizers that are normally applied to lawns. Obviously the more fertilizer that ultimately is absorbed by the root system the more healthy the grass will be. Pesticides that may be applied to a lawn also become more effective in loose soil. Earth worm activity is promoted and after several succeeding years of aeration, it is likely that a year can be skipped.
Seeding after aeration will produce excellent growth and any compost that is spread will settle into the small holes as a result of the coring process and add substantial fertility to the soil.
Aerating is a win-win proposition for the soil and the environment as well as the owner of a lawn that will be the envy of all who gaze upon it.