Fall Lawn Care Guide
By: Julie Day
Fall cleanup is important for keeping your lawn healthy.
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.
Warm-season grass, like St. Augustine, start to go dormant in the fall.
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 the 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.
Apply fertilizer on a cool day, and water it in.
Fertilizing Cool-Season Lawns
- Start feeding cool-season lawns in late August or September (6 weeks before your average first frost) with a 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.
Cool-season grass seed grows quickly in the fall weather.
Fall Lawn Seeding and Planting
- Cool-Season Lawns: Fall is the perfect time for establishing and thickening turf through seeding, sodding, and patching bare spots. If you’re seeding your lawn, reduce the amount of fertilizer to avoid burning the seedlings.
- Warm-Season Lawns: If you don’t like the brown appearance of your dormant warm-season lawn, fall is a good time to overseed with annual ryegrass or other cool-season grass for winter color. Apply the seed about 2-4 weeks before your average date of first frost.
A healthy lawn is the first line of defense against weeds.
Fall Lawn Weed Control
Fall is the ideal time to combat actively growing weeds with post-emergent herbicides. Weeds, like other plants, spend the fall drawing nutrients from their leaves into their roots for winter survival. The increased absorption means that your weed-control products will quickly be drawn into the roots for rapid results.
Other Fall Lawn Tasks
- Leaf Cleanup: If allowed to accumulate, leaves form a wet blanket that smothers your turf grass and invites disease. Keep leaves raked or picked up, and consider using them to start a compost pile. Small amounts of leaves can be mowed and mulched into your lawn.
- Mowing: Continue mowing as long as your lawn is growing. Mow newly seeded lawns as soon as they need it. Make sure your mower blades are sharp for the fall season, and do a little mower maintenance before putting it away for the winter.
- Watering: The weather may be getting cooler, but your lawn still needs one inch of water per week as long as it’s growing. Newly planted grass seed will need watering every day or two until established.
- Grass alternatives: If you have areas of your lawn where grass refuses to grow, fall is a great time for planting and establishing groundcover.