Depending on the variety, grass seed can take 5–30 days to sprout. To accelerate grass seed growth and ensure grass survival, spread grass seed at the right time. Warm-season grasses should be seeded in spring. Cool-season grasses should be seeded in fall.
Make sure soil temperatures are optimal for the grass species you’ve chosen. Grass seed will only sprout and grow quickly if soil temperatures are optimal for seed germination. Read on for more information on how long it takes grass seed to grow, as well as the best soil temperatures for each common turfgrass species.
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Grass Seed Germination Time
Time from grass seeding to germination depends largely on the species of grass seed you’re spreading. Some grasses germinate within 5–7 days, while others can take as long as 30 days before they sprout. Of course, if seeded at the wrong time, grass seed may not sprout at all or may die shortly after sprouting. It’s essential to follow guidelines based on grass variety.
Warm-season grasses are common in the southern United States, but they can also be found in transitional zones throughout the United States, as far north as Kansas and Missouri. Additionally, warm-season grasses are grown in coastal regions of Australia. When planning to seed warm-season grass, follow these guidelines:
- Should be seeded in spring.
- Seed when soil temperatures are 65–70℉ (18–21℃).
- Seed at least 90 days before the average first frost.
Warm-season grasses grow best in warm temperatures. By seeding in spring, you allow the grass seed to sprout and grow throughout the hot summer months. This results in a well-established yard that can survive low winter temperatures.
Warm-Season Grass Seed Growth by Species
When seeding warm-season grass seed, keep in mind the expected timeline before each species will sprout.
- Bermuda: 10–30 days
- Zoysia: 14–21 days
- Centipede Grass: 14–21 days
- Buffalo Grass: 14–30 days
- St. Augustine: seed is not effective for establishing St. Augustine. New St. Augustine is established with sod or plugs.
Many warm-season kinds of grass remain in the soil for quite a while before germination. Stay patient, watering the ground daily to keep it moist. It might take some time, but the grass seed will sprout.
Cool-season grasses are found in northern regions and transitional zones of the United States, as well as throughout Canada and Great Britain. In some warmer zones, warm-season lawns are overseeded with cool-season grass in fall, to create a green lawn year-round. When seeding or overseeding with cool-season grasses, follow these rules:
- Should be seeded in the fall.
- Seed when soil temperatures are 50–65℉ (10–18℃).
- Seed at least 45 days before the average first frost.
Unlike warm-season grasses, cool-season grasses struggle to grow in hot summer temperatures. If you seed cool-season grass in spring, a summer heatwave can kill your delicate seedlings. It’s best to seed in fall because cool-season grasses grow especially fast in fall temperatures.
Cool-Season Grass Seed Growth by Species
Cool-season grasses are often found in seed blends that include 2 or more species of seed. However, it’s not uncommon to seed a lawn with just one species of grass. Here’s a quick guide so you know what sort of growth rate to expect from common cool-season grasses:
- Kentucky Bluegrass: 14–30 days
- Perennial Ryegrass: 5–10 days
- Fine Fescue: 10–14 days
- Tall Fescue: 7–12 days
As you can see, some species of cool-season grass, such as Ryegrass, sprout incredibly quickly. Others, like Kentucky Bluegrass, can take several weeks. If you spread a grass seed blend that contains both of these species, expect to see the ryegrass come up first. Later, the Kentucky Bluegrass will sprout and fill in what may be a thin-looking lawn.
Can You Speed Up Grass Seed Germination?
The speed of grass seed germination is largely determined by species. But, if it’s seeded at the wrong time or under the wrong conditions, grass seed may not sprout at all. Here are ways to ensure your grass seed sprouts as fast as possible.
- Check your soil pH before seeding. Reduce soil acidity with lime if necessary.
- Fertilize with a slow-release nitrogen fertilizer before seeding.
- Make sure soil temperatures are optimal for your grass seed species.
- Seed in spring for warm-season grasses
- Seed in fall for cool-season grasses.
- Water soil deeply before seeding.
- Water soil daily after seeding. Soil should be moist down to 1–2 inches. Continue until grass sprouts.
By making sure your soil has suitable pH and is full of nutrients, you give grass seeds the fuel they need once they germinate. If the soil is too acidic or has poor nutrient content, the seedlings may not survive to break the surface. Your grass seeds will go to waste.
Once you’re sure your soil is ready for seed, spread seed at the right time and temperature, then provide moist (but not wet) soil for the seeds to take root in. You’ll see results fast and get a much thicker yard.
What Triggers Grass Seed to Germinate?
Grass seed germination is primarily triggered by soil temperature. Think of each grass seed as a tiny thermometer—once it senses that the temperature is right, it’ll start to grow. That’s why soil temperature is so important when seeding your lawn.
Once they germinate, grass seeds need adequate nutrients and water in order to sprout and break the surface. It’s important to provide the right conditions so you can turn a high percentage of seeds into growing grass.
How Long Does it Take for Grass Seed to Grow?
Grass seed germination rates depend on the species of the seed you spread. Ryegrass varieties may sprout from seed in as little as 5 days, while species such as Bermuda and Buffalo grass may take as long as 30 days.
The key is to spread grass seed at the optimal time of year and soil temperature for the species you’re growing. If you seed at the right time and provide adequate water and nutrients, the grass will sprout. You just may have to be more patient with some types of grass seed than others.