Core Cultivation
(Aerating) Lawns

Curtis E. Swift, Ph.D.
Colorado State University Extension
Tri River Areas

1. improves water penetration into compacted soils and through thatch and mat layers.
2. reduces water runoff. Runoff from turf areas may carry pesticide residues and fertilizers into neighboring storm drains and streams causing pollution problems.
3. improves fertilizer movement to the turf roots.
4. allows greater levels of oxygen to reach the soil in exchange for carbon dioxide and other gases.
5. enhances turfgrass shoot and root development
6. increases soil microbe activity at the depth of the aerator's penetration as well as in the thatch layer - resulting in reduced thatch and mat layers

The spike-type aerators that push a large solid spike into the soil increase compaction in heavy clay soils. Aerating is done to loosen the soil, not compact it further. Check with your Extension office for the best aerator to use in your soil or stick to the type that removes a plug of thatch and soil in the aeration process.

Core aeration is not recommended during the heat of the summer but in spring and fall. If aerating in the fall, do this when at least 30 days of favorable growing weather is anticipated to ensure turfgrass recovery.

Soaking the lawn a couple days prior to aerating should supply the water needed to allow the aerating tines to penetrate to their full depth. If the soil is too moist when aerated, the cores will be pushed to the bottom of the aeration hole causing compaction; if the soil is too dry, the aerator will not penetrate to the proper depth.

Placed on Internet May 25, 1996