For lawns in warmer climates that have grasses such as zoysia, St. Augustine, centipede and bermudagrass, they benefit from a September application of nitrogen fertilizer at a rate of 1 pound of actual nitrogen per 1000 square feet of lawn area. Subsequent applications of one-quarter to one-half of a pound of nitrogen fertilizer that also contains potassium can be applied every four to six weeks thereafter until your area has received its first frost; this will help your lawn to recover more vigorously the following spring.
For lawns in the northern region and cooler parts of the country that have primarily Kentucky bluegrass, fescue or ryegrass lawns, an application of a nitrogen lawn fertilizer in September is recommended. Apply at a rate of 1 to 1 1/2 pound of actual nitrogen per 1000 square feet of lawn area. If the pH of your lawn is too low, October or November is the time to apply lime to your lawn to raise it.
In addition to fertilization, fall is the time to tend to other maintenance tasks in your lawn. Competition from lawn weeds is lower in the fall than in spring and as such, it is the best time of year to do any seeding or overseeding. If there are still weeds in your lawn, they can be treated with an herbicide. They often continue to grow after other grasses have gone dormant, so it is safer to apply herbicides without risk to your desirable plants.
Recommended fertilizer rates and application suggestions should be determined by a complete soil analysis. If your lawn is generally healthy, maintenance applications of lawn fertilizer should be all that is required most years, but soil should be tested every few years even in healthy lawns. Use do-it-yourself soil kits available at most garden stores, or send a soil sample to your local cooperative extension or university lab. Sampling is inexpensive and will tell you exactly what you should apply to your lawn.