Fall and spring are the most important times of the year for establishing and strengthening lawns, as well as preparing them for the harsh temperatures of winter and summer. Here are some tips for taking care of your lawn in the fall.
About Fall Lawns
There are two basic types of grasses—cool-season and warm-season—with different needs and requirements:
- Cool-season lawns (fescue, bluegrass, and rye) have their peak growing season in the early fall. This is the absolute best time of year to establish, strengthen, and cultivate these types of grasses.
- Warm-season lawns (Bermuda, centipede, St. Augustine, and zoysia) wind down their growing season as the weather cools. Warm-season grasses go brown and dormant after the first hard freeze, so fall care for them focuses more on weed control and planning for winter color.
Fall Lawn Cultivation
When lawns are growing, they respond well to cultivation tasks that improve soil quality. Unless you’re planting a new lawn and can till up the entire area, lawn cultivation is done gradually, every year or two, so that the lawn grasses can recover. Here are the most important lawn cultivation tasks:
- Dethatching should be done during your lawn’s peak growing season, but only if the thatch layer is over ½ inch. For cool-season lawns, fall is a perfect time. Hold off on dethatching warm-season lawns until next spring.
- Core Aeration should also be done during your lawn’s peak growing season so that the grasses can quickly recover. It’s best to aerate cool-season lawns in the fall and warm-season lawns in the spring or early summer.
- Top-Dressing your lawn with topsoil mixed with other ingredients is a great way to finish up the cultivation process since it evens out lumps and improves soil quality. Top-dress after aerating, and seed any bare spots.
- Correcting Soil pH can be done in the fall for any type of lawn. Start by conducting a soil test to determine what amendments, if any, are needed for your lawn. Apply lime to acid soils or sulfur to alkaline soils according to the recommendations of your soil test.
|Task||Cool-Season Lawn||Warm-Season Lawn|
|Core Aeration||Fall||Spring/Early Summer|
|Correcting pH||Fall or Spring||Fall or Spring|
Fertilizing Fall Lawns
Whether you should fertilize your lawn in the fall or not depends on the type of grass you have.
Fertilizing Cool-Season Lawns
- Start feeding cool-season lawns in late August or September (6 weeks before your average first frost) with an N-P-K ratio of 3:1:2 or 4:1:2. The nitrogen will stimulate green shoots and thick growth. Most lawns benefit from about one pound of nitrogen per 1000 square feet. Check the instructions on the fertilizer bag for correct application.
- Apply winterizing fertilizers, which are higher in potassium to promote winter hardiness, around the time of your last mowing of the season (October to November).
Fertilizing Warm-Season Lawns
- Stop feeding warm-season lawns in early August to late September (6-8 weeks before your average first frost). Do not fertilize warm-season grasses in the fall, unless you live in a frost-free climate, since this will stimulate growth as they are going dormant for the winter. Instead, wait until the growing season begins in spring or early summer.
- Winterizing Fertilizers: While there’s some debate about the usefulness of winterizer fertilizers, it’s generally recommended not to apply anything to warm-season grass after August.