Frost seeding, also known as surface seeding, is spreading grass seed on dormant lawns in late winter or early spring when the ground is frozen. The seed is left on the surface to wait out the winter and then germinates when temperatures warm and the ground thaws in the spring.
How frost seeding works
Frost seeding occurs during late winter or early spring while it’s still cold before your grass starts growing for the season.
Grass seeds are broadcast on top of the soil when temperatures fluctuate between freezing at night and thawing during the day. This fluctuation creates a condition known as freeze-thaw action, as repeated freezing and thawing cause the ground to crack and heave. The seeds naturally settle into the cracks in the ground without extra soil preparation.
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.”
As the snow melts and spring rains occur, the moisture waters the seeds, aiding germination.
Historically, frost seeding has been widely used in pasture management, primarily to improve forage stands of alfalfa, clover, and some grasses. It is less common in landscaping but is a valuable tool for enhancing and rejuvenating thin lawns.
Since no soil prep is performed to ensure good seed-to-soil contact, this method relies on frost heaving to improve this contact over broadcasting seeds on the ground and not working them in. The freeze-thaw cycle fosters better germination and seedling establishment.
Because the seed isn’t worked or pressed into the soil, frost seeding success depends on soil conditions (compaction and thatch), climate (the number of freeze-thaw cycles), and other factors, sometimes leading to uneven or unpredictable results. Research on alfalfa stands show a 60% to 70% success rate for farmers. Frost-seeding lawns can be expected to see the same rates when conditions are suitable.
While frost seeding does have significant benefits, traditional overseeding is favored by many homeowners and landscaping contractors due to its more predictable results. According to the University of Massachusetts Amherst, germination rates and survival range from 50% to 95% when overseeding. Under ideal conditions, you can expect higher rates; with good conditions, a 70% success rate can be expected.
Benefits of frost seeding
While it may not prove as successful as regular overseeding, frost seeding your lawn has benefits, making it an attractive option for some homeowners looking to improve lawn quality and fill bare spots.
- Frost seeding is easy and cheap. It requires less manual labor (no soil prep) and is more cost-effective than traditional overseeding. It is a fantastic way to establish new species in an undisturbed lawn at a low cost. Illinois Extension says it is “thought to be the simplest and least expensive method of seeding.”
- Grass starts growing as soon as the weather warms up, giving it a head start over weeds. This head start helps grass establish better since it doesn’t compete with weed seedlings for water and nutrients. It also reduces weed seed germination when the new grass shades the soil.
Best practices for frost seeding
- Frost seeding works best for cool-season grasses, which germinate and vigorously grow when temperatures are cooler in the spring.
- Choose turfgrass species that germinate quickly, like perennial ryegrass and turf-type tall fescue.
- The ground should not be completely frozen or covered in snow. However, you do want it cold enough that it’s experiencing freeze-thaw cycles.
- Like traditional seeding, good seed-to-soil contact is still essential with frost seeding. Aerate or dethatch your lawn in the fall before the ground freezes.
- Once the ground thaws, avoid heavy foot traffic. Stay off the seeding area to prevent disturbing the seeds before they can germinate and take root.
FAQs about frost seeding
When should I start frost seeding?
Frost seeding should be done in late winter or early spring, with the exact timing depending on your local climate and type of grass seed. In most cases, this is typically sometime between late February and early April, and it should be done approximately 40 to 50 days before your grass starts growing for the season.
Can you frost seed warm-season grasses?
Frost seeding doesn’t work well for warm-season grasses; it is better suited for cool-season species germinating in early spring. Warm-season grasses like Zoysia and Bermudagrass germinate when soil temperatures are between 65 and 70 degrees Fahrenheit and air temperatures range from 80 to 95 degrees Fahrenheit. Frost seeding these species leaves the seed on the ground longer, increasing the chances it will get eaten by birds or small animals or washed away by rain before it germinates.
Should you fertilize when frost seeding?
When you frost seed, the ground may be frozen or partially covered with snow, so there is no need to apply fertilizer simultaneously. Once it thaws and temperatures warm, follow your regular fertilization schedule.
Are there soils you shouldn’t frost seed?
Yes, frost seeding isn’t as effective on compacted soils, soils with thick thatch, and waterlogged or poorly drained soils. If possible, it’s best to aerate or dethatch to improve those conditions before frost seeding.
You should avoid frost-seeding rocky, gravelly, or sandy soils. Dan Undersander of the University of Wisconsin Extension says, “frost seeding is not recommended for sandy soils because the freezing and thawing does not incorporate the seed.”
Let the experts help
Frost seeding is a fantastic way to improve lawn thickness or vitality. It’s much less labor-intensive than traditional overseeding, but Lawn Love is here if you need an extra hand. Whether prepping the ground the preceding fall 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.
Main Image Credit: Conservation Media Library | Flickr | CC BY 2.0
