The best time to plant warm-season grass seed is late spring or early summer, or when temperatures hover near 80 degrees or higher in your area. Plant cool-season grass seed in late summer or early fall (when daytime temperatures lower to about 60 to 75 degrees) for best success.
The ideal temperature range for grass seed is between 55-85°F (12-29°C). Anything below 55°F (13°C) will inhibit the growth of your grass seeds, so it's important to keep an eye on the weather forecast when planting. In cooler climates, you may need to wait until spring or early summer before planting your lawn.
During the summer, when temperatures rise, atmospheric and soil temperatures become too hot for cool-season grasses to grow and flourish. Once temperatures reach 77 degrees, it becomes too hot for root growth, and root growth ceases.
Much like established grass, grass seed will struggle to grow in high temperatures. But unlike established grass, where air temperature is more important, grass seed is much more dependent on soil temps. Most grass seed will germinate when soil temperatures are consistently between 55-70 degrees.
Daytime temperatures should be averaging between 60 and 85 degrees which translates to soil temperatures between 50 to 75 degrees.
If the daytime temperature is below 60°F then soil temperature is below 50°F, making it too cold; if there is frost or still a danger of frost, then it's too cold. If it's too cold, the grass seeds will likely rot.
The best month to put grass seed down depends on the type of grass you have. The best time to plant grass seed for cool-season grasses is in early fall or around September. For warm-season grasses, late spring or early summer is the optimal time.
Most people might think of Spring as the best time to start a new lawn, but the truth is that late Summer and early Fall are far better for starting a new lawn from seed. Any time after August 15th is prime lawn time; the warm soil in combination with cooler air temperatures will encourage far better seed germination.
If you simply toss the grass seed onto the soil, you will end up with poor germination. Thoroughly rake the area to remove any loose debris and to create grooves in the soil. These grooves will help increase the seed-to-soil contact that is imperative for germination.
If you put down too much grass seed, you will encourage competition that will cause your grass seedlings to struggle after germination because there will be excessive competition for sunlight, soil nutrients, and water. You'll know if you seeded too heavy when the grass grows in very thick patches.
The best time to water your grass seed is early in the morning or after the sun has begun to go down. Watering when the sun is directly overhead is counterproductive and on a very hot bright day not only can be wasteful, as water evaporates faster in heat, but can actually be harmful.
Although a low-cut, manicured lawn might seem ideal, turf grass actually does better in the summer heat when you let it grow a bit. Longer shoots mean deeper roots, which the lawn needs to suck up whatever moisture is in the soil. A higher lawn also shades the soil, minimizing evaporation.
High temperatures over 90 can kill the plant inside the seed.
Grass can turn brown and go dormant when it's stressed by drought, heat, or both. It's your lawn's way of conserving energy and water, Mann explains. The grass will break dormancy and begin growing again when the temperatures and/or rainfall levels become more ideal for it.
Prep the lawn for seeding
Luckily, getting it right is easy. 'To prepare your soil before planting grass seed, simply till and loosen the soil to create the best growing conditions – you don't need to put down topsoil,' says Jeremy Yamaguchi, CEO of Lawn Love.
Whether you're repairing bare spots, overseeding an existing lawn or starting from scratch, you can generally expect grass seedlings to emerge within seven to 21 days when grown under proper conditions. It may take another three to four weeks of growth before grass is long enough to mow.
Grass seed is surface sown, meaning lays and roots on top of the soil, so it does not need to be buried. It's usually broadcast over the ground with a hand or rotary spreader. In order for that seed to sprout, it needs good soil contact, which makes soil quality a major factor in growing a healthy, uniform lawn.
Technically, yes. Planting a lawn is as simple as sprinkling seeds on the ground. But if you're growing grass on hard dirt, you should prepare and aerate the soil before. Also, it's important to sprinkle the seeds during the grass's peak growing season and mix them slightly with the dirt.
Days to Soak How long it takes for grass seed to germinate depends on the species. Turfgrass seeds can be soaked in water for 3 to 5 days to germinate. Kentucky Bluegrass (KBG) is slow to germinate and should be soaked for five days.
In most cases, if you are simply adding seed to a thinning lawn it is not necessary to rake in the grass seed. If you are seeding a new lawn or there are bare spots, then you will need to rake in the seeds.
New grass should be watered twice a day (or more under dryer conditions) to keep the top two inches of soil moist at all times. Water daily until all of the grass seeds have germinated, then it will be ready to begin a regular watering schedule.
Known for its resilience, grass seed can typically last anywhere from two to 10 years, although the germination rate presented on the seeds' package drops by 10 percent every year.
Use a “mist – lightly water – deeply water” process like this: After seeding and fertilizing, you'll want to keep the top inch of soil moist until the seeds start to germinate (aka sprout). This means misting the area once a day, maybe twice if it's unusually hot out there—but don't let the area get soggy.
The best time to water grass seed is in the morning and evening. These are the coolest parts of the day, which allows water to absorb into the ground instead of evaporating.
Make at least 3 applications of seed, each a week or so apart. More applications are fine, too. Applying a large amount of seed to the lawn gives the competitive advantage to the perennial ryegrass over the weed seeds which are already lurking in the soil.