"Many homeowners see spring as the most critical season for lawn care," says Bryan Ostlund, executive director of Grass Seed USA, a coalition of American grass seed farmers and turf specialists, "but in reality, at least in the transition and cool zones of the U.S., fall maintenance can have just as much impact - if not more - on the year-round health and appearance of your lawn. Once temperatures are consistently below 60 degrees, your lawn will start storing up nutrients in preparation for winter. That's when you should start your fall lawn care regimen."
Following are three proactive measures you can take in the fall to ensure lush green grass come spring.
Before you reseed, mow your lawn and remove the clippings, and then prepare the soil by raking with a straight rake. This will remove dead organic matter and loosen up the top half-inch of soil to improve contact with the seed. Then apply a high-quality seed that is appropriate for your local climate conditions and is resistant to currently prevalent pests. Ask your local extension office (see https://nifa.usda.gov/land-grant-colleges-and-universities-partner-website-directory for a directory) for recommendations of blends that have tested well in your area. You'll want to use fresh seed, so check the label to confirm that the seed was tested within the past 12 months. After planting, water the reseeded area lightly and regularly to keep it damp until the new grass is established.
Although new warm-season lawns are best planted in the late spring or early summer, if you live in the warm zone you might consider overseeding your warm-season turf with cool-season grass seed in the fall. The cool-season grass will thrive until the warm-season grass turns green again in the spring, ensuring year-round color.
Aerify. Aerifying your lawn combats soil compaction and thatch buildup and enables water, nutrients and oxygen to reach the grass's roots more easily. You can hire a professional to aerify your turf for you, or you can rent a core aerator that uses hollow tines to pull up small plugs of soil at regular intervals throughout the lawn. If you're reseeding, aerify right before you apply the new seed.
Apply fertilizer. Cool-season grass should be fertilized in the fall - even if your lawn looks perfectly healthy and has no bare patches - to promote good root development, enhance the storage of energy reserves and extend color retention. Most of the benefits of fertilization will be seen the next spring and summer, with earlier green-up, improved turf density, greater tolerance to spring diseases and reduced weeds.
Note that new grass and established lawns need nitrogen, phosphorus and potassium in different proportions. So if you're reseeding, apply a starter fertilizer at the time of planting and then follow up with a second application, this time using standard fertilizer, four to eight weeks after germination. Your extension office can help you determine which fertilizers are best for your type of grass and local conditions.
Investing a bit of time and effort in fall maintenance will pay off next year, with greener grass earlier in the spring and a thicker, healthier lawn that is ready to stand up to the rigors of summer wear and tear.