Below are some great tips from Better Homes and Gardens on Fall Lawn Care
Fertilizing: If you only feed your lawn once a year, autumn is the best time to do it. In fact, your lawn could take a light application of fertilizer in early fall and again in late fall.
Water on Schedule
Most lawns need water whenever it's dry -- no matter the season. If drought persists into autumn, water once or twice per week long enough to soak the soil several inches deep. Early morning is the best time of day to irrigate because winds are usually lighter so you'll waste less water to evaporation. Avoid watering in the evening because that encourages fungal diseases.
More mowing: It seems like it never ends: As temperatures cool, your lawn will grow faster. You'll likely need to mow regularly through the end of the season.
Adjust Your Mowing Height
If you raised the height of your lawn mower in summer to reduce heat stress to your lawn, return the mower deck to its normal mowing height (about 2 inches tall is best for most grasses) in fall. Cutting your lawn slightly shorter in autumn helps prevent the grass from matting down under leaves and snow. Avoid cutting the grass too short, however. Tightly clipped turf has fewer roots and allows weeds to get a foothold.
Overseeding: Most grasses in the Midwest grow best when it's under 75 degrees F. -- making autumn the ideal time to overseed. Be sure to give your new grass about a month before your first average first frost so it can get established. Overseed warm-season lawns with ryegrass each autumn. This type of grass provides a lush, green carpet through the cool winter months. Prepare the lawn for overseeding by mowing it 1/2 inch shorter than usual and removing the clippings. Sow grass seed over the mowed area, making two passes at right angles to each other.
In the North, overseed thin lawns or large dead areas. Keep the newly seeded sections moist while seeds sprout. Frequent light sprinklings are best at first. Gradually increase the interval between waterings to encourage the roots to grow deeper into the soil.
Learn about the differences between cool-season and warm-season grasses.
Go after perennial weeds: Most perennial lawn weeds are most susceptible to attack in fall when they're winding down and getting ready for winter. Tackle them with a broadleaf herbicide or pull them by hand.
Dandelions, clover, and other broadleaf weeds are easy to spot in spring, but fall is the best time to rid your yard of these pests. Perennial weeds readily send herbicides containing glyphosate, 2, 4-D, and MCPP applied as a spray or granules to their roots in fall. Sprays work best on days with moderate temperatures and when the soil is moist.
Check out our weed identification guide.
Repair Dead Patches
Early fall is a great time to reseed any small dead or thin patches in cool-season lawns. If you seed in autumn, you'll have fewer weeds. And the seedlings will become established before stressful hot weather conditions arrive. A mulch product embedded with seed and fertilizer is a convenient way to fill the gaps.
Spring or fall is a good time to start a new cool-season lawn or patch existing turf with sod. Moderate temperatures and abundant moisture get sod off to a quick start. High-quality sod will be thick, dense, and weed-free. It's a convenient way to get an instant solution to bare spots.
Get easy step-by-step instructions for laying sod.
Check for Thatch
Thatch is a layer of dead organic matter mixed with living plant parts that can lead to disease and insect problems as well as damage from drought and cold weather. Thatch may develop when you overfertilize your lawn or water too frequently. Check for thatch by removing a plug of grass and soil. One-half inch of thatch or less is not a problem. If there is more than that, your lawn is ready for a thatch-management program. (See the next slide for tips on dealing with thatch.)
Remove Excess Thatch
Dethatching involves cutting through the thatch layer and ripping out the debris. Power rakes or vertical mowers are effective tools for this. Use a hand rake to remove the thatch from the lawn after it has been pulled out by one of these machines.
Note: Power raking and vertical mowing can damage centipedegrass, St. Augustinegrass, and others that spread by surface runners. Use a machine that has knives correctly spaced for these grasses.
Aerate: Cooler autumn temperatures mean your grass will start growing more again -- so it's a great time to aerate to loosen compacted soil.
Aeration reduces thatch, improves drainage, and loosens soil. Make sure that the aerator you use pulls plugs of soil from the turf rather than simply punching holes in the ground, which actually increases compaction over time. Aerate cool-season grasses in early fall and warm-season grasses in spring.
Check out our other organic lawn-care tips.
Apply a Top Dressing
Top dressing means applying a thin layer of soil or compost to your existing turf. The process improves growing conditions by reducing thatch, increasing the amount of organic matter in the soil, smoothing bumps in the lawn, and lessening the need for fertilizer. Spread a thin layer of equal parts loam, sand, and peat. Be sure to dethatch or aerate before you apply a top dressing. Then work the top dressing into the soil by raking it in.
Remove Fallen Leaves
Remove fallen leaves by raking them or mulching them with a mower before they mat down and smother your grass. A mulching mower works well to shred small amounts of leaves and returns the shredded organic matter to the soil, much like top dressing. When many leaves are present, rake them off the lawn and compost them.
Drain Irrigation Lines
Completely drain your lawn's irrigation system before freezing weather arrives. You can empty the system with compressed air or use drain valves. For best results, shut off the water to the system and drain each zone separately. Also drain the main supply line from the house. If you use an air compressor, don't exceed 50 psi of air pressure.