HAMPTON, Iowa — Sowing grass seed at the optimal time of year, selection of a high-quality seed mix appropriate for the site, and consistent watering are keys to successfully establishing grass from seed.

Mid-August to mid-September is the best time to seed new lawns and overseed existing lawns. Late summer seeding has several advantages over spring seeding. The seeds of cool-season grasses germinate quickly in the warm soil of late summer. The warm days and cool nights of early fall promote rapid turfgrass growth. The growing grass also has less competition from weeds, as few weed seeds germinate in fall. Grass seed can also be sown in April to mid-May. However, spring seeding is often less successful than late-summer seeding.

When purchasing grass seed, choose a high-quality seed mix that is best adapted to the site. In sunny areas, Kentucky bluegrass is the best choice. Select a seed mix which contains at least two or three bluegrass cultivars. Perennial ryegrass is often included in many bluegrass seed mixes because of its ability to germinate and establish quickly. Use a mixture containing Kentucky bluegrass, perennial ryegrass and fine-leaf fescues in areas containing sun and shade. The fine-leaf fescues (creeping red fescue, hard fescue, chewings fescue, etc.) are the best grasses for shady locations.

After seeding, keep the upper inch of soil moist with frequent, light applications of water. Two light applications of water per day are usually sufficient. However, it may be necessary to water three or four times on windy, sunny days. The seeds of most turfgrasses should germinate in two to three weeks if the seedbed is kept uniformly moist. Gradually reduce the frequency of watering, but water more deeply, when the grass seedlings reach a height of 1 to 2 inches.

This article was submitted by Iowa State University Extension and Outreach.