When it comes to planting cool-season grass seeds, frost seeding and dormant seeding are two popular methods. Both techniques involve seeding during colder months when germination and active growth are inhibited, but they differ in ways, including timing, soil preparation, and whether they work better for establishing a new lawn or improving an existing one.
Understanding the key differences between the two types of seeding can help you choose the best method for your lawn, ensuring successful germination and healthy growth.
What is frost seeding?
Frost seeding is a method of overseeding that involves spreading grass seeds on dormant lawns in late winter or early spring when the ground is frozen. This method is only effective, obviously, in areas that experience temperatures cold enough to freeze the soil.
Grass seeds are broadcast on top of the soil (with no soil preparation) when temperatures fluctuate between freezing at night and thawing during the day. This temperature fluctuation creates a freeze-thaw action — the repeated back-and-forth between freezing and thawing causes the ground to heave and subside, resulting in cracking.
The seeds naturally settle into the cracks in the ground, negating the need to prep the soil before broadcasting seeds.
Joshua Michel and Rebecca Vittetoe of Iowa State University Extension and Outreach explain, “The goal of frost seeding is to get the seed in contact with bare soil. For this reason, frost seeding on top of snow cover should be avoided. If snow accumulates after you’ve frost-seeded on bare ground, that is perfectly fine.”
The seed is left to wait out the winter and germinates when temperatures warm and the ground thaws in the spring. As the snow melts and spring rains occur, the moisture keeps the seeds and soil well-watered, enhancing germination.
What is dormant seeding?
Dormant seeding involves seeding a lawn in late fall or winter when the soil is cold enough to prevent germination. The seeds remain dormant through the winter, sprouting when the ground warms in the spring.
Also known as cold seeding, winter seeding, or snow seeding, this seeding option is the most effective where winters are cold and wet.
Like traditional overseeding, the ground is typically worked to loosen its top. Seeds are broadcast across the surface and then raked into the soil or lightly covered. Winter rain and snow then help to work the dormant seeds further into the soil, away from birds, wind, and storms.
Once the soil gets warm enough in the spring, buried seeds germinate among the first plants on your lawn. Melting snow and spring rain ensure proper soil moisture, often without watering.
Differences between frost seeding and dormant seeding
Timing
Frost seeding is done in late winter or early spring when the ground is frozen at night and thaws during the day. This timing takes advantage of the freeze/thaw cycle which improves seed-to-soil contact.
Dormant seeding is done in late fall or early winter when the soil is cold but not frozen; it is most effective when soil temperatures range between 45°F to 55°F, preferably below 50°F. In the northern U.S., this time is October to early November. In the transition zone, late November to early January is considered the ideal time for dormant seeding.
Soil preparation
With frost seeding, you don’t need to work the soil to ensure good seed-to-soil contact; it relies on the frost heaving to move the seeds into the ground. With dormant seeding, you prepare the soil by loosening the top inch like you would for traditional fall or spring seeding. One of the most effective ways to loosen the soil is to use a bow or garden rake (not a leaf or lawn rake) to break up the very top of the soil, ensuring better seed-to-soil contact.
The seeds are then broadcast over the soil. After being spread, they are lightly worked in using a rake, or the entire area is rolled or lightly tamped down for improved seed-to-soil contact.
Fertilization
With frost seeding, you don’t fertilize simultaneously; with dormant seeding, you do.
When you frost seed, the ground may be frozen or partially covered with snow, so there is no need to apply fertilizer simultaneously. Any fertilizer applied then wouldn’t make its way into the ground. Once it thaws and temperatures warm, follow your regular fertilization schedule.
When dormant seeding, you can apply either your regularly scheduled late fall fertilizer or a starter fertilizer — make sure not to apply both. Since the ground isn’t frozen, the nutrients will work into the soil.
Lawn type
Frost seeding a new lawn is possible, but isn’t typically recommended. It is generally more effective when trying to thicken or rejuvenate an existing lawn. This is because it relies on the freeze-thaw cycle to move seeds down into the soil and isn’t always predictable or uniform.
Dormant seeding works well for both new lawns and overseeding existing grass.
Cost-effectiveness
Frost seeding is cheaper than overseeding since there isn’t any need to prep the soil before broadcasting. All you need to do is purchase seed, and perhaps a spreader.
- Kentucky bluegrass seed can be anywhere from $7 to $12 per pound.
- Perennial ryegrass costs $2.50 to $9.50 per pound of seed.
- Tall fescue costs between $3 and $10 per pound.
Dormant seeding costs the same as overseeding or seeding a new lawn as the process is the same. It’s just done at a different time in the season.
- Dormant seeding costs between $490 and $1,250 on average.
Similarities between frost seeding and dormant seeding
Grass species
Both seeding methods work best for cool-season grasses, which germinate and vigorously grow when temperatures are cooler in the spring. The methods don’t work well for warm-season grasses like Zoysia and Bermudagrass that germinate when air temperatures range from 80 to 95 degrees Fahrenheit and soil temperatures are between 65 and 70 degrees Fahrenheit.
Frost seeding or dormant seeding these species leaves the seeds on the ground longer, increasing the chances they will get eaten by birds or small animals or washed away by rain before germination.
Delayed germination
Neither method intends for immediate germination. Both plan on the seeds germinating when temperatures warm in the spring. This early spring germination gives the seedlings a jump-start over weed seeds that may take longer to sprout.
Moisture reliance
Both methods count on adequate soil moisture from snow melt or spring rains to aid germination. This reliance on natural moisture sources is extremely convenient for the homeowner, helping to cut down on the constant need to water new seed prior to germination.
Pre-seeding lawn care
Both seeding techniques work better if you aerate and dethatch your lawn before seeding. Aeration helps break up soil compaction, making it easier for new roots to grow into the ground. Removing the accumulated thatch layer helps seeds reach the soil surface.
FAQs about frost seeding and dormant seeding
What are the benefits of frost seeding and dormant seeding?
- Early establishment of grass in the spring.
- Grass starts growing as soon as the weather warms up, giving it a head start over weeds.
- Improved root development and grass growth before harsh summers arrive.
- Works well for overseeding bare areas and thin lawns.
What happens if you dormant seed too early?
If dormant seeding is done too early in the fall, a warm spell can trigger the seed to germinate just before winter. The young seedlings aren’t likely to survive a hard frost or upcoming freezing temperatures, wasting your seed, money, and time.
What happens if you frost seed too early?
If you spread the seed too early in the winter season (e.g., before the freeze/thaw cycle occurs), there’s a risk that rain, wind, or snow melt could wash away or blow off the seed before it has a chance to work into the soil. This can lead to patchy growth or poor establishment once temperatures are suitable for germination in the spring.
Need expert help?
Frost and dormant seeding are fantastic ways to improve lawn thickness or vitality. However, this project may not be one you want to tackle alone. Don’t worry — Lawn Love is here if you need an extra hand!
Whether prepping the ground by aerating, seeding the lawn, or applying fertilizer to keep your new grass looking its best, we can connect you with a local lawn care professional.
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