Grass seed needs the correct soil and air temperature, as well as moisture content, to sprout. If planted at the right time, grass seed will have sufficient time to grow and spread its roots, creating a thick and vibrant lawn.
Plant grass seed at the right time for the specific type. Cool season grasses, which are typically grown in the northern states, should be planted in the early spring or early fall. Warm season grasses, which are grown in warmer states, should be sowed in late spring or early summer.
Grass slows down its growth during temperature extremes. Planting grass seed too early or too late can result in gaps in your lawn. Not only do grasses need a certain temperature range to sprout, they also need a specific amount of time until they are strong enough to survive.
It's possible to grow grass outside the typical growing season, but the risks are higher. The seeds may rot from the cold and moist soil, or they can be killed by freeze or frost. Hot summers can also kill off seed before it has the chance to germinate properly.