As you’re working your way through your fall gardening checklist, you may have questions about what to do to your lawn before winter sets in—like whether aerating is involved. There are a few different factors to consider, but if you decide the aerate your lawn, now’s probably the best time to do it. Here’s what to know.
Do you really need to aerate your lawn?
Technically, no: Though your lawn will certainly benefit from aeration, says Tom Kalb, a horticulturist with the North Dakota State University Extension, most lawns don’t need it in order to survive.
So, how do you know if your lawn is one of those that need it? According to Kalb, the lawns that gain the most from aeration include those:
That get heavy foot traffic
That have excessive thatch (>1 inch thick)
That are grown on heavy soils
If yours falls into any of the categories above, it would probably benefit from annual aerating. Otherwise, he says it’s best to aerate once every one to five years for optimal growth.
When is the best time of year to aerate your lawn?
Most people opt to aerate their lawn in either spring or fall—but which is better? According to lawn experts at the University of Maryland Extension, it depends on whether your lawn consists of warm-season grasses or cool-season grasses.
Here’s how the U.S. Department of Agriculture defines the two:
Warm-season grasses grow mostly from June through early September, are well-adapted to hot, dry weather, and will still be green in July and August
Cool-season grasses grow best in the spring and fall when soil and air temperatures are cooler
While June and July are best for aerating lawns with warm-season grasses—like those grown in the southern parts of the U.S.—cool-season grasses grown in the rest of the country benefit from fall aeration, and are our focus today.
But don’t put off the lawn care task: Fall aeration should be done in September or October.
The benefits of aerating your lawn in the fall
So, what makes fall the best time to aerate cool-season grasses? Here are a few benefits of fall aeration, according to a horticultural educator at the University of Illinois Extension:
It makes your lawn denser, which creates competition for weeds
It improves water drainage in compacted soil, which can make the lawn less susceptible to disease, as well as weeds like yellow nutsedge, prostrate knotweed, and spotted spurge
It makes it easier for water, air, and nutrients to reach the root zone
If you’re also overseeding in the fall, the holes from aeration can help the seeds come in contact with the soil, and improve germination
If you’re new to aerating, or aren’t sure where to begin, check out this previous Lifehacker post, which will walk you through the process.