Everyone wants a thick, healthy lawn– but the truth is that getting a picturesque dream yard isn't always easy. Aside from ensuring the right equipment, you must provide the perfect timing to plant the grass seed. This includes determining the ideal grass seed germination temperature, so all your effort, time, and money won't waste.
Generally, the ideal temperature for grass seed germination ranges between 9 and 12 degrees. It will also depend on the type of grass you're planting. Cool-season grasses sprout best in the fall, with soil temperatures of 50 to 65 ℉ (or 10 to 18 ℃). This includes bluegrass, Fescue, and rye. Meanwhile, warm-season grasses are best seeded in spring with soil temperatures of 65 to 70℉ (or 18–21℃). This includes Bermuda grass, centipede grass, and Zoysia.
To ensure that your grass seed thrives, you must provide the ideal conditions with the right moisture and warmth for proper germination.
The Best Temperature for Grass Seed Germination
Unfortunately, all your soil preparation and seed sowing activities will be useless if you plant your new grass seed at the wrong time. You will need to consider both seasonal times and ideal temperature ranges as you plant the seed for your lawn. The young seedlings may die or fail to germinate outside these recommended time frames.
Warm-Season and Cool-Season Grasses
Your grass seed will either germinate or stay dormant depending on the soil temperature it has been planted upon. Experts recommend soil temperature mapping to determine whether it's the right time to seed your lawn. But, there are plenty of ways to make a sound judgment of soil temperatures.
Cool-Season Grass Seed
As previously mentioned, cool-season grass germinates best with a soil temperature of 50 to 65 ℉ (or 10 to 18 ℃). This includes the likes of: Bentgrass, Kentucky bluegrass, Tall fescue, Annual ryegrass, and Perennial ryegrass.
Warm-Season Grass Seed
The ideal soil temperature for warm-season grass seed germination is 65 to 70℉ (or 18–21℃). This includes Bermuda grass, centipede grass, and zoysia grass.
Other Factors that Determine the Ideal Grass Seed Germination Temperature
Here are some factors that can determine the temperature of an ideal grass seed germination:
Time of Year
Several homeowners tend to apply grass seed once the yards have been raked thoroughly in the spring. But, spring weather can often be unpredictable. When grass seed fails to germinate during the spring, this is usually because of the wet and cool weather. When grass seed is sown in soil temperatures below 50 degrees Fahrenheit, it may fail to germinate for the next few weeks.
To ensure your soil temperature reaches more than 50 degrees, you must ensure that the outside temperature is 65 degrees (or higher) for at least ten days. In the spring, some areas are prone to frequent rainfalls as well. Heavy rains can only delay your grass seed germination.
Cool-season grass seeds, in particular, grow well during the fall as they experience strong germination and healthy growth before winter. There's a second substantial growth period sometime in the spring. Similarly, warm-season grass seeds benefit when seeded in spring since they will thrive for the summer.
The grass seed type you plan to grow will influence the ideal temperature requirements for its grass seed germination. As such, you need to know whether you are seeding a cool or warm season grass seed. Keep in mind that several commercial grass seeds blend different seed types with varying germination rates. Hence, always check the list of grasses included in your grass seed.
Here are some considerations when seeding with this warm-season grass:
St. Augustine Grass
This warm-season grass adapts to hot, humid environments. St. Augustine grass is known to spread by above-ground stolons or "runners."
Zoysia is a popular warm-season grass with benefits similar to Bermuda and St. Augustine grass.
Kentucky bluegrass is a hardy cool-season grass popular from transitional zones to northern areas of the United States.
Here are some essential considerations when seeding this crowd-favorite cool-season grass:
This next cool-season grass suits residential lawns in the country's cold, northern regions. It is also commonly used as an overseeded seasonal grass in the warmer states.
Water & Soil Contact
The grass seed must be planted no more than ½ inch in-depth, with the top 1 inch of the soil kept moist. As long as you follow proper watering with the correct grass seed germination temperatures, achieving the picturesque, lush green lawn you've always wanted is easy!
Ensuring your new grass sprouts and develops well won't be difficult as long as you've researched. Before purchasing grass seed, ensure that you know exactly what grass type it is to determine the best time in the year to plant it. If you know the recommended grass seed germination temperature for your new seed, you're well on growing a green, healthy lawn!
Frequently Asked Questions (FAQs)
What temperature does my soil need for seeds to germinate?
Soil temperatures must be above 50 degrees Fahrenheit for spring seeding and dormant seedlings to germinate. A temperature range of 50-65 degrees is ideal (measured at a depth of 2 inches). The germination process will start once reaching this soil temperature.
What temperature is too cold for grass seed?
In extreme cold or freezing temperatures, grass seed will not germinate. Even cool-season grasses will grow slowly or cease growing when temperatures drop. Furthermore, it's important not to expose young grass seedlings to frost or freezing temperatures since this might kill them.
What temperature is too hot for grass seed?
Although warm-season grasses continue to thrive throughout the summer, many cool-season types of grass go dormant when temperatures get too high. As a result, depending on the temperature, seeding grass in the middle of summer may not be the best option.
Why are soil temperatures and air temperatures so different?
Soil serves as an insulator. The pore space is made of water and air, making it a good insulator. These pore spaces either maintain freezing temperatures when they reach a low level or extremely hot when they reach a high level. Because of these insulating properties, transitioning from warm to cold or cold to warm might take a long time.
What factors can affect soil temperature?
It can be affected by number of pore space, depth of the soil, plant cover, frost, and water level.