Seed your fescue in the fall, as this will give your lawn its best chance to get established. When daytime temperatures reach down to 65 to 75 degrees Fahrenheit, the soil temperatures are usually between 55 and 65 degrees. Your fescue seed will germinate best in these cool temperatures. Wait until about eight weeks before frost in the fall to seed your fescue, which in most states means seeding in late September or October. When temperatures get below 50 degrees, fescue can go into dormancy. An early freeze or frost can kill seedlings that are immature and have not had enough time to get deeply rooted. However, you can plant early enough in the fall to give the young plants the best growing conditions for the longest period of time.
Seed fescue in the spring if you did not have a chance to do it in the fall. Wait until the soil temperatures are between 55 and 60 degrees, but try to plant it early enough so it can get fulled rooted before the warmer temperatures arrive. Usually March and early April are good times in the spring to seed fescue. Seeding fescue in the spring means you need to be conscientious about watering. When temperatures rise above 90 degrees, fescue has a tendency to go dormant. Usually this means the grass turns to a pale green during the hottest part of the season. Do not plant when the temperature rises above 70 degrees.
Overseed your lawn if it is looking too thin or has patchy areas. Fescue grasses are naturally dense, but some lawns benefit from overseeding every other year. Overseed fescue preferably in the fall when roots have more time to establish before the next summer. Some lawns that are difficult can benefit from overseeding in the fall and spring, but if insects or disease is a problem for your lawn, always overseed in the fall.