You mow your lawn, you fertilise your lawn, but you may not remember to aerate your lawn. Yearly aeration reduces soil compaction and breaks through layers of thatch, ensuring healthy turf from the roots to the blades.
Spike aerators push solid tines into the soil. They are not as efficient as core aerators, which remove a plug of soil and deposit it on the lawn surface. Both styles are available as manual rollers or as more efficient mechanical aerators.
Aerate at least to the depth of your lawn's roots. Use a shovel to determine the depth. Aerator tines may reach from 1 inch, which is fairly ineffective, to 6 inches. According to the Colorado University Extension, aerate as deep as possible, spacing cores 2 inches apart.
Mark sprinkler heads and shallow utility or cable lines before aerating. Do not aerate new lawns for the first year. Water the lawn 2 days before aerating to soften the soil, but do not aerate muddy or wet lawns.