Establishing a new lawn in Ohio by planting grass seed can be a tricky process. It's most likely to be successful if you plant at the right time and give the new grass seedlings proper care until they're established.
Choosing Grass Varieties
The best varieties of grass for Ohio turf are cool-season species. These grasses grow actively during the spring and fall and go dormant in the hottest part of the summer. They are well adapted to climates like Ohio's, where summers can be hot but winters are cold. Warm-season species, which are less cold-tolerant, generally do not do well in Ohio.
Species well suited to Ohio include Kentucky bluegrass (Poa pratensis), tall fescue (Festuca arundinacea) and fine fescues (Festuca spp.), which are all hardy in U.S. Department of Agriculture plant hardiness zones 2 to 7. Most of Ohio falls into USDA zone 6, although some pockets of USDA zone 5 are scattered throughout higher elevations around the state.
The ideal time to plant cool-season grasses is in the late summer, when temperatures are relatively low and rain is frequent. If you plant seed in early summer or mid-summer, the seedlings will face stress from high temperatures and drought, as well as competition from weeds, and are unlikely to survive. If late-summer seeding isn't possible, spring seeding may work, but planting time must be as early as possible to give the grass plenty of time to get established before summer heat sets in.
In Ohio north of Interstate 70, the ideal seeding time is throughout the month of August. South of I-70, the optimal seeding window extends as late as mid-September. For spring seeding in the northern half of the state, plant between the beginning of April and the middle of May. In the southern part of the state, plant between the middle of March and the end of April.
Adding organic material to the soil before you seed will help to improve the soil's nutrient content and its moisture-retention capabilities. To amend the soil before planting, spread compost over the entire area to be seeded to a depth of 1 to 2 inches, then use a tiller to incorporate the compost into the top 6 inches of the soil.
Seeding and Watering
Sow grass seed with a broadcast spreader at a rate of between 1 and 8 pounds per 1,000 square feet depending on the grass variety you're planting. After seeding, rake the soil lightly to cover the seed, and then cover the area with a thin layer of straw.
Water to keep the surface of the soil consistently moist until the seed germinates. If the weather is especially warm and dry, you may need to water twice a day or more.
Sowing new grass seed over existing turf can help to rejuvenate a lawn that is beginning to thin or show bare patches. Before overseeding, mow the turf to a height of 1 to 1 1/2 inches and aerate with a core aerator. For best results, sow the seed with a slit seeder, which ensures good contact between the seeds and the soil. Lightly cover the seed with a top dressing of compost, and keep the seed moist until it germinates.