Frost germination is a traditional term for cold stratification. And frost germination says what it means. Exposing sown seeds to natural frost can often give them the right signal to sprout. Haven’t we often found that Mother Nature knows best? Allow Mother Nature to work, with a little help, by planting seeds in prepared pots or bed, early in winter. Then let snow, frost, cold and sleet give seeds what they need.
Play with your seeds even in the face of frigid forecasts. Some seeds like it cold. The seeds of certain plant species must endure cold and wet in order to grow. Skilled gardeners know how to plant seeds before the snow flies. This method allows the economical growing of perennials, wildflowers, shrubs, and trees from seed.
About Sally G. Miller
Frost germination and natural cold stratification
Cold stratification means exposing seeds to moist, chilly conditions for some period of time before planting. But why do some seeds need this treatment, and others do not? Some plants have a longer, slower life cycle, and they need to ensure that their seedlings develop well for the long haul. Many wildflower, perennial, shrub, and tree seeds need stratification. Seeds that "sleep" until very early spring grow into strong seedlings during spring’s milder temperatures and steady soil moisture. Sturdy seedlings can endure the stress of summer. They are well grown before winter returns.
Snow may make you want to curl up under the blankets, or bake up a storm of carb-laden goodies. Snow makes some seeds wake up and want to grow. Snow is wet and cold. Happily, it is the moisture and cold that some seeds need to get busy. When the weather report has you getting the snow shovel and salt bucket handy, let it also remind you to look through your seed stash for seeds that need cold stratification.
Answer: We recommend cool-season grasses here, including bluegrass, the fescues, and perennial rye grass. We don’t recommend throwing down grass seed on the snow, since that leads to very uneven seed distribution when the snows melt and water runs down slopes and off the lawn. However, as soon as the snow melts and the ground is not too wet, it’s fine to go ahead and scatter grass seed over your lawn to do some over-seeding. Mid-February through late March is a good time to sow cool-season grass seed. Once the ground is no longer frozen or muddy, you can even rent a slit seeder to get good seed to soil contact as well as a more uniform distribution of seed. Early March seedings usually have fewer problems with weed competition than April/May seedings.
Question: Someone told me it’s a good idea to throw down grass seed on top of the snow, and it will grow in the spring. Is that true?
Problem lawns in Northern Kentucky with shade, poor soil, or heavy traffic should almost always be established with tall fescue. Fine (red) fescue and perennial rye grass also have some limited uses in lawns. Bluegrass seeds take much longer to germinate, and eventually thatch buildup can become a problem, requiring de-thatching.
Do a soil test (free through your local Northern Kentucky county extension service) now to determine the exact lime and fertilizer needs of your lawn. Excess lime can result in poor nutrient uptake. Only by having your soil tested will you know whether or not you should add lime, phosphorus and potassium to your lawn soil.
Ideally, seeding of new lawns should be done into loose, prepared soil. Seeding is usually done with a rotary seeder or the usual drop-type seed and fertilizer spreader. To determine the proper seeding rates, ask for a copy of Cooperative Extension publication, “Selecting the Right Grass for Your Kentucky Lawn (AGR-52).” For uniform distribution, divide the seed into two equal lots. The second lot should be seeded at right angles to the first. Cover the seed by raking lightly or rolling with a water-ballast roller. Mulch the area with clean straw. The mulch covering should be thin enough to expose about 50 percent of the soil surface, which means using about one bale of straw per 1,000 square feet of area. If snows and rains cease, water the new grass seedlings often, but lightly. For weed control, refer to Cooperative Extension publication, “Weed Control Recommendations for Kentucky Bluegrass and Tall Fescue Lawns and Recreational Turf (AGR-78).”