In order to thrive, turf lawns need to be porous enough to allow oxygen, water, and nutrients to penetrate down to the root zone. Lawns that are too compacted or which have too dense a thatch layer can prevent air, water, and nutrients from getting down to the roots.
Aeration is any process that breaks up the soil surface or perforates it in a way that allows air and water to access the roots. It can also help relieve thatch buildup and encourages deep rooting of the grass plants.
Methods of Aeration
Aerating can be done several ways. Core aerating is done with a motorized rental machine that uses hollow tines or forks to remove plugs of the turf. The holes provide an entry point for the nutrients, air, and water, but should not be regarded as preparation for seeding. While core aeration is a good precursor to seeding, the lawn will need additional preparation in order for grass seeds to germinate.
After aeration, the plugs are usually left on the surface and are ground up and worn away by subsequent mowings or a vigorous raking. At this time, the lawn can also be topdressed with loam, compost or other soil amendments.
Aerating can also be done with solid tines. In this method, no core is removed, so topdressing and overseeding are slightly less effective. But the lawn surface is still penetrated, allowing for improved air, water and nutrients uptake and some relief of compaction. With method is considerably less effective than core aeration, but will still improve a badly compacted lawn.
Aerating is usually accomplished with a walk-behind machine with hollow or solid tines mounted on a drum which propels the machine forward, poking holes along the way. Aerating can also be done with simple tools like a pitchfork, a pitchfork-like tool with hollow tines, or even sandals equipped with long spikes.
A foot-operated core aeration tool is also available. It operates like a shovel and is designed to simply remove a couple of plugs with each step of your foot. This would be a labor-intensive job if you have a large lawn, but aerating a few small compacted areas after each mowing will keep a small lawn in good shape.
How Often to Aerate
Few homeowners aerate often enough. Some homeowners are reluctant to aerate because they find the plugs visually unattractive. However, these plugs quickly dissolve and decompose, and are actually good for the lawn. Or, they can be raked up. Other homeowners fear that aeration damages the lawn. This is not the case. While another lawn care practice, dethatching, is an aggressive action that may damage a lawn, core aeration does nothing but good tings for a lawn.
Aerating is most effective when done every fall, especially if it is done in conjunction with overseeding and fertilizing as part of a complete lawn care program. However, renting an aerator can be costly, and the act of aerating is physically strenuous. Hiring a lawn service to do it can be even more costly. Aerating every other year or even every three years is acceptable if the lawn sees low use.