In the fall and early winter, lawns become dormant. Lawns require less care late in the year, but they can benefit from a bit of preparation for the winter sleep. Take care of your lawn at the end of the season and it'll begin spring fresh, green and vibrant.
If you live in a northerly region with good snow cover all winter, use dormant seeding to get an early start on filling gaps in your lawn next spring. Spread new seeds on the lawn in late fall before the first snow or hard frost so that they get good contact with the ground. When the snow melts in the spring, the seeds will germinate and grow new grass early in the season. Dormant seeding is susceptible to unusual weather, which makes it a bit risky. If there is an early thaw, your seeds may begin to germinate only to be killed again when the temperature drops.
Lower the Cutting Height
In the fall and early winter, prepare your lawn for winter dormancy by shaving it closer and closer to the ground. According to All About Lawns, you should gradually lower the lawn height to "one inch for warm-season grasses and two inches for cool-season grasses." At this height, your lawn will trap less moisture, which will make it less susceptible to winter and early spring diseases.
According to Ed Hume Seeds, there are a few autumnal diseases that can affect your lawn. "Dirty, white, tan, or brown patches" are often signs of a fusarium patch, also known as snow mold. Treat your lawn with a fungicide immediately to halt the spread of the disease. Red thread usually appears as "pink spots or webbing... on the lower blades of the grass." This disease can be treated by applying a fall fertilizer. Lawns are also vulnerable to insect damage in the fall and winter. If your lawn has recently been infested by insects or you suspect an infestation, treat it with an insecticide.