Does Your Lawn Need Aeration?-Two

When Do You Aerate? It Depends On Your Turf

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. 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 work 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 grasses emerge from summer dormancy in early fall and grow vigorously during the lower temperatures and reduced weed competition typical during this season. 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. Early spring (after you have mowed twice) is the second best time to work cool-season lawns.

Warm-season turf types — aerate in late spring / early summer:

Bahiagrass

Bermudagrass

Buffalograss

Centipedegrass

St. Augustinegrass

Zoysiagrass

Cool-season turf types — aerate in fall:

Creeping Bentgrass

Fescue (Chewings, Hard, Red, Tall)

Kentucky Bluegrass

Rough Bluegrass

Ryegrass (Annual, Perennial)

Know Your Soil

Different soil types require more frequent aeration. Clay soil compacts easily and should be worked 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. But if your lawn is frequently driven on or used for parking cars, you’ll need to annually.

Timing Tips

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 for newly-planted lawns, so that grass is well established.

Work 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 work in these conditions, you’ll stress the lawn by allowing heat to dry soil.

TLC For Aerated Lawns

Afterward, leave soil plugs in place to decompose. These cores contain microorganisms that digest lawn thatch. Running over them the next time you mow will break them up, as will a light raking (after they dry out) or dragging a piece of old carpet over the lawn.

You can fertilize and seed lawns immediately following aerating. It’s not necessary to add a thin layer of soil or composted manure, but you can. For heavily compacted soils, consider covering the lawn with one-quarter inch of compost (use sand in southern locales), raking it so it falls into aeration holes.

Core aeration brings up weed seeds from lower soil levels. For cool-season grasses, plan to use a pre-emergent herbicide in the spring following fall aeration. For warm-season turf, apply the herbicide the fall after aerating. Do not apply a pre-emergent herbicide at the same time you reseed.

Water your lawn a few extra times following aeration, especially during hot or dry spells.