Just like you wouldn’t mow a lawn that’s soaking wet or apply a winterizer fertilizer in June, aeration also requires specific timing. The time of year you tackle aeration and how often you aerate depends on grass and soil type.
Know Your Turf
Lawn grasses fall into two different categories: warm-season and cool-season. Warm-season grasses begin their period of active growth in summer. If you aerate a warm-season lawn in late spring to early summer, the ensuing period of rapid growth will quickly fill in the holes you create.
Cool-season turf emerges from summer dormancy in early fall and grows vigorously during the lower temperatures and reduced weed competition typical of fall. Strong growth helps the lawn quickly recover from the stress of aeration. The caveat on fall aeration is this: Time aeration to allow four weeks of growing time prior to frost.
Warm-season turf types – aerate in late spring / early summer:
- Bahia grass
- Buffalo grass
- Centipede grass
- St. Augustinegrass
- Zoysia grass
Cool-season turf types – aerate in fall:
- Creeping bentgrass
- Fescue (chewings, hard, red, tall)
- Kentucky bluegrass
- Rough bluegrass
- Ryegrass (annual, perennial)
Aeration Varies With Soil
Different soil types require more frequent aeration. Clay soil compacts easily and should be aerated at least once a year. You can aerate a sandy lawn once a year, or you could tackle the chore in alternating years. In arid climates, aerating twice a year will enhance turf growth and health. If your lawn is frequently driven on or used for parking cars, aerate annually.
- When you know you’re going to aerate, do so just prior to fertilizing or reseeding your lawn. Aeration creates openings for nutrients and seed to penetrate soil.
- Control weeds prior to aerating, because the process of aerating can spread weed seeds or portions of weedy roots.
- Wait for at least a year to aerate newly planted lawns, so that grass is well established.
- Aerate when soil is moist, but not saturated. The tines of a lawn aerator penetrate moist soil more deeply; soil that’s too wet clogs tines. To achieve the correct moisture balance, your lawn should absorb 1 inch of water – delivered through rainfall or irrigation – prior to aerating. This may mean you’ll water for one hour one day prior to aerating or, if your soil is hard, for shorter times on several days prior to aerating.
- Avoid aerating during drought or high heat. If you aerate in these conditions, you’ll stress the lawn by allowing heat to dry soil.