Fall is the best time to seed your lawn if you have a Cool Season Grass.
Cool season grasses are varieties like tall and fine fescue, which are very common throughout the Southeastern United States, in areas like North Carolina. Other cool-season grass varieties include Kentucky bluegrass and perennial ryegrasses. These are the grasses that you see really green and lush early in the spring through summer, but right now may be browning out during dormancy to protect itself from the hot and dry temperatures.
When you seed your cool season lawn during the fall, particularly during the earlier part of the season, you’ll find that you sprout good results! Seeding your lawn now works well because the temperatures are cooling down and the risk of drought is passing. The soil is also still warmer from the summer sun. Aim to plant your seed at least 30 days prior to your region’s first estimated frost. Of course, depending on the year weather might be conducive to extend the seeding window even longer. If your soil is too cold, it is harder for the seed to properly germinate. Warm, nutrient-rich soil creates an optimal environment for seed germination and allows new seed to establish and thrive quickly.
After seeding your lawn, you should begin to see your seedlings begin to emerge within 3 weeks of planting. Varieties like tall fescue germinate fairly quickly. You should begin to notice seedlings within 14-21 days. Once your lawn seed begins to come in, you will need to wait another 3 weeks to 1 month prior to mowing. You should not mow your new grass until it has reached proper mowing height so that you can ensure the root system has time to strengthen. In some cases, depending on the weather, this may mean waiting until spring arrives before you mow. Preparations of your lawn prior to seeding is key here. You should mow at 2.75”-3” just before applying seed. This will enable at least two weeks to keep the mower off the lawn.
Spring and early summer is the best time to seed your lawn if you have a Warm Season Grass.
If you have turfgrass varieties such as Bermuda or Zoysia, the best time to seed your lawn is in the Spring. This is because warm-season grasses do not tolerate cold temperatures as well and typically go dormant (ie turn brown during the late fall and winter.
Care instructions for seeding your warm season lawn are similar to those noted above for cool season grasses. However, you may find it beneficial to take additional steps like de-thatching your lawn prior to seeding if you notice a thick layer of thatch just above the soil. This will help airflow better reach the new seed.