The Best Time to Plant Grass in New Hampshire

Warm Season Grasses

• Warm season grasses like switch grass, bluestem, and Indian grass are best seeded between April 15 and May 15. They grow best when warm nights follow hot days, so take full advantage of the New Hampshire summer, and allow the grass to grow strong enough to withstand winter dormancy.

Cool Season Grasses

• Cool season grasses like bluegrass, alfalfa, and timothy grow best when the days are warm, but the nights are slightly cool. These grasses undergo growth periods both in the spring and fall. In New Hampshire, late August through September is the best time to seed, because the seedlings will go through a complete growth cycle before winter sets in. Seeds can be sown in spring as well, but weeds germinate at this time. Fertilizing the lawn will also fertilize any new weeds. Weeds enter dormancy in the fall.

Dormant Seeding

• Grass seed can also be sown in late winter in New Hampshire, when the ground is still frozen, but the snow has melted away. The seed will enter dormancy and will not germinate until the ground reaches 55 degrees Fahrenheit. The ground will freeze nightly and thaw daily, drawing the seed gently into the topsoil.