Fall maintenance is a crucial part of maintaining a lush, healthy lawn. During the fall months, grass is actively storing nutrients and energy to prepare for the winter season. Proper lawn maintenance throughout the fall can help strengthen root systems, improve disease resistance, and ultimately lead to a healthier, stronger lawn. 

Mowing

Grasses, especially cool-season grasses like Kentucky bluegrass, continue to grow through the fall. Because of this fall growth, continue mowing your lawn until the first frost hits. In mid to late September, adjust your mowing height to 2.5-3 inches. This length is long enough to allow effective photosynthesis to take place but short enough to prevent the grass from matting under the snow. Along with adjusting your mowing height, you can also adjust your mowing frequency. As grass growth begins to slow down, adjust to mowing once a week or on an as-needed basis to keep the grass at the proper height. Regular mowing in the fall can also help to mulch leaves and other fallen plant material, which can help to return nutrients to the soil. 

Watering

While the cooling temperatures may tempt you to bring in your hoses and turn off your sprinklers, lawns may still need weekly watering through the fall. Ideally, your lawn needs about 1 inch of water per week, including rainfall. If rainfall is scarce during the fall, try to do deeper waterings less frequently. This style of watering will help to support your grass while encouraging the roots to grow deeper into the soil. To reduce the risk of fungal development, water in the mornings so that your lawn has plenty of time to dry before nightfall. Monitor your lawn for signs of improper watering, such as wilting, discoloration, fungal diseases, or premature dormancy, and adjust your watering schedule if needed. 

Fertilizing

Fall fertilizing helps to promote strong roots and provides essential nutrients that your lawn needs to fuel growth next year. Proper timing and application can have a significant impact on your lawn’s winter survival as well as spring growth. Choose a slow-release granular fertilizer that has a balance of nitrogen and potassium, such as a 24-0-10 formula. Nitrogen will help to promote leaf growth, while potassium will aid in root development. Apply the fertilizer around mid-September to early-October. This gives your lawn enough time to absorb the nutrients and put on some late-season root growth. Use a broadcast spreader to evenly apply the fertilizer and water thoroughly after application. Always follow the product’s recommended application rate to prevent burning.

Aeration

Aeration is an often-overlooked aspect of fall lawn care that can have a significant impact on your lawn’s health. Over the years, your soil becomes compacted, and thatch accumulates. Regular aeration, once every couple of years, can alleviate soil compaction, prevent thatch buildup, and help increase water and nutrient movement within the soil. For the most effective aeration, use a core aerator on a moist lawn. Dry soil can prevent aerators from penetrating deep enough to be effective, and wet soil can plug up your machine. Properly aerated lawns should have 20-40 holes per square foot, so you may have to do several passes with the machine. 

Late Summer Seeding

One of the best times to start a new lawn or to overseed an existing lawn is mid-August through mid-September. Late summer seedings have many advantages over other forms of seeding. First,  grass seeds germinate quickly as the soil temperatures are already warm from the summer. Second, the warm days and cool nights during the fall promote rapid root and turf growth. Third, few weeds germinate in the late summer, so there is less weed competition to choke out the new grass. 

When seeding a new lawn, the first step is to prepare your soil. To establish a lawn, you need 4 to 6 inches of good soil. If you have heavy, clay, or poor soil, it may be necessary to mix in new topsoil to the top 6 inches of soil.  After the soil is prepped, apply your grass seed of choice with a drop-type seeder to ensure that the grass seed is uniformly distributed. Make sure to follow the application rates found on your seed bag, as different seed mixtures may have different application rates. Once the seed has been spread, lightly rake the area to ensure good seed-to-soil contact. The grass seed should be covered to a depth of 1/8th to 1/4th inch. To promote seed germination and prevent soil erosion, mulch the area with clean, weed-free straw. Mulching the area also helps to keep the soil moist and prevents the soil surface from crusting. Apply your mulch so that 50 percent of the soil is still visible through the straw. Too dense of mulch can smother the emerging seedlings. After your initial watering, water the area frequently and lightly so that the seedbed does not dry out during the germination period. The goal is to keep the top inch of soil continuously moist.  Depending on the temperature and humidity, daily watering may be necessary.

When overseeding a lawn, ensuring good seed-to-soil contact is crucial for successful overseeding. In years when you aerate, you can overseed right after aeration as the soil holes provide good soil contact. For years when you do not aerate, mow your lawn to a height of 1.5 to 2 inches before overseeding. This helps to reduce the competition from your existing lawn. If there is a lot of dead grass, rake to de-thatch the area to expose the soil underneath before spreading your seed. Once you have spread your seed, water frequently and lightly so that the seedbed does not dry out. Keep the top inch of soil continuously moist through the germination period. To prevent burning of the new seedlings, wait a few weeks after the turfgrass has emerged before applying a starter fertilizer. 

Weed Control 

Fall is the best time to get control of perennial broadleaf weeds, as these weeds are actively taking up nutrients in preparation for winter. Broadleaf herbicides that are applied in the fall will be absorbed by the weed’s foliage and taken up by the root system, resulting in the death of the weeds. When using herbicides, follow all product instructions carefully and spray when temperatures are cool to prevent burning of your grass. 

Raking and Leaf Removal

In the fall, leaf debris can accumulate and block light from reaching the turfgrass. If the leaves are not raked and removed, the lack of light can lead to lawn dieback and patchy areas of weak grass. Leaves can be collected by raking, blowing, or using a collection bag while mowing. These leaves can then be disposed of or added to a compost pile. Make sure all of the leaves are removed before it snows to prevent fungal problems such as snow mold from developing.