Spring and fall are the recommended times to plant cool-season grasses. Why not summer?

For Kentucky bluegrass, perennial ryegrass, and fescues, summer presents several challenges to germination and growth.

Most cool-season grasses go dormant once soil temperatures exceed 65°F, which is normal in the summer. Planting cool-season grass during the summer months is a bad idea because germination and seedling survival rates would be low.

Summer annual weeds, as the name suggests, are active during the summer months. They compete for nutrients with other plants, and seedlings are no exception. Waiting until fall to seed allows annual weeds to complete their life cycle so seedlings can grow with less competition. 

Disease pressure is strong in the summer. Seedlings are unlikely to survive a disease infestation on top of heat stress and competition. Rather than seeding during the summer, focus on fungicide applications to manage disease pressure.

Insects are another threat to summer seeding. During the summer months, grubs feed on the roots of young turfgrass plants. Seeding in the summer may do nothing more than feed the grub population or, at best, grow plants with weak root systems.

Controlling weeds, diseases, and insects during the summer will be good preparation for a successful seeding come fall.