LATE SUMMER AND FALL are great times to plant grass seed
In central Ohio, it's been a decent growing season for lawns. We didn't have prolonged periods of summer drought, which typically causes lawn grasses to go dormant or even die, and precipitation has been adequate to keep most lawn grasses green and growing throughout the summer.
Even with these beneficial growing conditions, some homeowners may have bare spots in their lawn or thinning stands due to heavy use or other conditions.
Although most homeowners think about rejuvenating bare spots in the lawn or a complete lawn renovation in the spring, the best time of year to plant new lawn grass is late summer and early fall.
Cool-season plants
Lawn grasses are cool-season plants, which means that they thrive in the cooler temperatures and moist soil conditions of spring and late fall, as opposed to the hot dry summer months. That explains why you can hardly keep your grass neat and trim in April and October with a weekly mowing, but can stretch out mowing chores to every 10 days or more during the dog days of summer when cool-season grasses can stop actively growing.
In central Ohio the optimum time to plant cool-season grass seed is from Aug. 15 to Sept. 15, if soil moisture is not in a severe drought state. With recent precipitation, conditions during this planting window is nearly ideal this year.
Fall ideal for planting
A late summer or early fall seeding is typically more successful that a spring seeding because the soil is still warm, which allows new seedlings to quickly develop healthy root systems before going dormant after a hard freeze. Typically, threre is a much quicker germination of grass seed planted in the fall, usually within four to six days after seeding, than with spring seedings that sometimes
take 10 to 21 days to germinate.
The cooler air temperatures that we typically experience in the fall are also more beneficial to above-ground growth of the leaf tissue of grass plants, and these cooler temperatures are less conducive to development of leaf diseases of lawn grasses. There is also less competition from most weeds at this time of year.
Preparing the seed bed
If you are new to the seeding process, here are tips to follow:
• Prepare a proper seed bed for lawn grasses by removing weeds and thatch from the area to be seeded.
• When overseeding into thinning existing stands of desirable grasses, cut these stands shorter than normal to allow for good seed-to-soil contact and allow for maximum sunlight for germination. Bare soils that have crusted over can be scored by scraping the top inch of the soil with a bow rake. A thin layer of compost can be added to the top of the soil for added fertility and organic matter.
• For most central Ohio homeowners, blends of Kentucky bluegrass and either a perennial ryegrass or a fine fescue should be the species of choice.
• For a complete list of different turfgrass species for lawns and their characteristics under different environmental conditions and management strategies go to: go.osu.edu/turfgrassspecies.
Don’t be afraid to mow
New seedings should be mowed when they grow to a height of 21⁄2 to 3 inches, which is typically three weeks after seeding. You don't want new plants laying down in a mat before they are mowed for the first time.
Be careful when turning with the lawnmower, especially with riding mowers, as new-lawn grass seedlings can easily be pulled from the ground when they are young. It is always best to mow new seedings with a sharp mower blade, so get that blade sharpened now and you won't need to worry about it next spring.
If we don't receive adequate rainfall of at least an inch per week in September and October, be ready to provide irrigation for new seedings.
Mike Hogan is an associate professor at Ohio State University and an educator at the OSU Extension.
hogan.1@osu.edu