The latest you should sow grass seed in North Carolina is mid-October. This gives the seedlings time to become well established and grow into a thick lawn before the hot summer weather arrives the next year.
Grass seed mixtures grow better than single types because they combine the positive attributes of the individual grasses. Mixtures better handle soil moisture and temperature conditions, as well as fight off turf diseases.
North Carolina soil commonly suffers from a low pH, making it acidic. Plan to amend the soil six months before planting grass seed. Add agricultural grade limestone, following the results of a soil test.