In most parts of the country, grass is best planted before or after the summer, according to This Old House. Otherwise, it is difficult to keep the seeds moist during the summer, without watering them constantly.
The fall is an ideal time to plant grass seeds in most parts of the United States. This is the best time to keep the seeds moist for germination. Moreover, weeds that compete with grass are dead during the fall, which allows the grass to grow well. Grass planted in the fall can mature before facing the summer stress, such as mowing, heat, inappropriate watering, competition and traffic.