It seems like a simple problem. If there are places where grass isn’t doing well in the yard, it’s time to throw a handful out there, right? Not necessarily. In this article, we’ll get into the how, when and why of the best time to plant grass seed.
What is grass?
Grass is a monocot plant, meaning it emerges with a single leaf after germination. Some grasses are annuals, meaning they grow for a year, drop seeds and die back. Other grasses are perennials, often growing using reproductive methods other than seeds, including creeping stems and roots, sets and other forms. Grass also comes up in a seasonal fashion, but that will be covered in the next section.
Grass that reproduces by seed alone spends most of its energy trying to reach a height where seeds can be dropped for the next year’s growth. Over time, this causes natural selection in favor of grasses that can remain close to the ground and still form and drop seeds. Grass that spreads by creeping stems, otherwise called stolons, have an advantage in that they need not reach a particular height to spread. Many “weed” grasses such as crabgrass spread in this fashion.
Cool versus warm season grasses.
Watching a lawn through the seasons, it becomes apparent that different varieties of grass grow during different times of the year. That’s because there really isn’t a good one-size-fits-all grass. Having a mixture of grasses seeded into a lawn allows it to adapt to changing weather conditions. The simple way to tell the two types apart is that cool season grasses brown in the summer, while warm season grasses brown in the winter. There are guides available to help determine exactly what cool season and warm season grasses are already growing in a lawn, which are more likely to be successfully reseeded there. However, this also means the best time to plant grass seed isn’t always a simple answer.
Cool weather grasses include Kentucky Bluegrass, tall fescue and annual ryegrass, which are seeded early in the spring, often a month or two before the area’s last frost date, or in the fall, which are much more successful because of reduced competition from crabgrass and other invasive weeds. Fall plantings should be in the month or two before the first frost date. Warm season grasses include bahiagrass, bermuda grass, buffalo grass, carpet grass, centipede grass and zoysia grass, which can be sown when soil temperature is above 70 degrees F.
What needs to be done first?
Before jumping in at the right time of year for planting, some important questions must be answered. Why did the grass die back? Is there an overly friendly neighborhood pooch who prefers that particular spot to tinkle? Is the soil pH off? Was it not getting enough fertilizer or a particular nutrient?
If any of these questions can be answered with a yes, soil amendment may need to take place first. If there are multiple dead spots, take a soil sample and bring it to your local county extension office, run by the land grand university in your state (University of Texas, University of Missouri and University of California all being examples). For a small fee, usually under $20, they’ll run a comprehensive soil test to determine what needs to be changed in the soil. Once the results are back, fertilizer can be applied as needed to bring the soil back within range that it will successfully grow grass.
Now that it has been determined what type of grass seed is best, what to do before planting it and the best time to plant grass seeds, it is time to drop some seeds. Start by removing the thatch – dead grass and leaves – covering the soil. Make sure the soil is clear or debris – I would recommend getting a good leaf blower to help make the job easier. If a large area needs to be dethatched, some rental stores carry dethatching equipment, which may take two to four passes to remove all the thatched material. A slit seeder or seed drill rented from an equipment company will minimize surface disruptions; stirring up the soil will usually bring weed seeds to the surface to thrive instead of your selected grass species.
Once the seed is in good contact with the soil, it can be covered with a light layer of straw to keep it from washing away. If broad leaf weeds become overly competitive with the new grass, a broad leaf-specific herbicide can be used to control the weeds, or they can be hand-pulled if the infestation is not too bad. Weather is important when using herbicides; wait for a dry, sunny day with no risk of frost before applying it.