Here’s a good article on lawn care by the BH&G Garden Editors for Better Homes & Gardens.
Take advantage of cool fall weather to fertilize, control weeds, and improve the health and appearance of your yard. A little work now will pave the way for a lush, green carpet when temperatures warm up again in spring.
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 3 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.
Consider Watering
If a summer drought persists into autumn, consider watering your turf deeply a couple of times before freezing weather sets in. A couple of deep soaks, moistening the soil several inches, before the soil freezes helps the lawn transition to winter. Frequently the fall weather pattern will change and nature will provide the moisture for you. If you have to water, do so in the morning when the winds are lighter, limiting evaporation.
Apply Fertilizer
Fall is the best time to fertilize your lawn if you live in the North. Cool-season grasses, such as bluegrass, fescue, and ryegrass, respond well to feeding in early September and again in late fall (late October or November). It helps them green up earlier and look better in spring.
Avoid fertilizing dormant warm-season grasses in the South unless they have been over seeded with winter ryegrass.
Attack Weeds
Creating a healthy, lush lawn is the best way to choke out weeds, instead of relying solely on chemical herbicides. Focus on mowing at the proper height, aerating as needed, and adding fertilizer to provide essential nutrients. Smaller weeds usually will get shaded out when your lawn is in top shape. For larger weeds, break out your weeding tools and pull up these pesky plants, roots and all. If you must use a spray, follow all label instructions carefully and target just the weeds you want to kill rather than treating your entire lawn.
Repair Dead Patches
Early fall is an ideal time to reseed dead or thin patches in cool-season lawns. If you seed in autumn, you’ll have fewer weeds to deal with next year. 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. Be sure to prepare the soil bed with a rake before seeding and encourage quick germination by watering new seed regularly for a couple of weeks after application.
Lay Sod
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. If conditions turn dry, be prepared to water new sod daily.