Frozen assets: Frost seeding an option to improve forage

Frosty berseem clover emerges from the winter ground. The new variety is the first berseem clover to be cold-resistant down to 5 degrees Fahrenheit, making it a great option for frost seeding. Courtesy photo.

Ask farmers to describe a “typical” April day, and you’ll get a variety of responses: Rain. Snow. Wind. Freezing. Sunshine. Tornados. Flooding.

The gamut of weather conditions during prime planting time can vary, and the workload crammed into “nice days” can get heavy.

Frost seeding is a somewhat paradoxical but effective planting method that allows farmers to win a hand with Mother Nature, even on her terms. Implemented in the late winter months while the ground is still frozen, frost seeding is simply broadcasting seed – normally a cold-tolerant legume – directly onto frozen soil, preferably with little to no snow cover. Subtle movements of the soil through freezing and thawing cycles allow the seed to embed up to a quarter-inch in the ground. By the time the soil has thawed and dried enough to get a tractor and drill on the ground, the seed will ideally have already germinated and established a stand – allowing for a head start on the growing season. Or, the seed can be spread on locations where a drill is not feasible or a current stand of other species needs to be supplemented.

Frost seeding has been around for a long time, says Risa Demasi, co-owner of Grassland Oregon, an international plant genetics company based in Salem, Ore. “There are some risks associated with it, but for unique situations, frost seeding is a great alternative that can improve legume stands in fields or pastures.”

An example of a situation that would be a good fit for frost seeding is a field where winter-kill has eliminated a stand of alfalfa. Here clover or other legumes can be frost-seeded to “fill in the gaps” and improve yield. “We are likely to see a lot of winterkill this year,” says Demasi, “so this could be something people consider.”

Pastures that producers are seeking to improve nutrients from are also prime locations for frost seeding, by planting a desirable grazing legume before the growing season. Jerry Hall is a plant breeder and also co-owner of Grassland Oregon. He says the earlier establishment of seed into the soil allows new seedlings to better compete with established plants while the present plants are still dormant.

Hall says one challenge is seeds that germinate on the surface are still subject to winterkill. “Due to this it can be more difficult to establish full stands when compared to drilling, and thus seeding rates should be higher.”

Lance Lindbloom is an agronomist with 406 Agronomy in Havre, Mont., and has seen success with frost seeding. In his previous work as a farm manager in Nebraska, Lindbloom says he broadcast red clover and white clover seed along with spring fertilizer into a hay field that was predominantly cool and warm season grasses. “Basically we were trying to fill holes in the ground, and add a legume to the mix,” he says. “The idea was the clover would have an opportunity to grow and replace other undesirables.”

Lindbloom says they used a reduced seeding rate, but implemented the practice over several years. “The first year or so we didn’t see a whole lot of difference, but after that the clover became a good percentage of the stand.”

He added that currently in the agronomy industry there is a lot of attention paid to frost seeding grain crops. “It’s a different topic, but the same philosophy.”

Producers thinking about frost seeding should consider the following factors:

  • Evaluate seed species and varieties

Red clover has long been noted as the best choice for frost seeding – clovers in particular have a smaller, slick seed and are more likely to settle into the soil. Other species that work well include white clover, birdsfoot trefoil, perennial ryegrass, orchardgrass and smooth bromegrass. A recent variety of berseem clover developed by Grassland Oregon called “Frosty” is being promoted for its ability to withstand temperatures of down to 5 degrees Fahrenheit, making it a great fit for the frost seeding model. It is not recommended to use timothy or reed canarygrass for frost seeding, nor alfalfa, as they are not as cold-tolerant.

  • Seed to soil contact

Ideal sites for frost seeding are fields or pastures with bare or exposed soil. Generally no-till fields with crop residue are not good locations because the seed will not easily reach the soil. Pastures that will be candidates for frost seeding can be grazed down to a lower-than-normal level in order to expose more soil previous to frost seeding.

  • Consider seeding rate

Broadcast seeding is not as efficient as drilling, so in most cases seeding rate should be bumped up slightly to compensate. However, contrarily, some producers opt to distribute the risk of frost seeding over several years and use a reduced seeding rate, but repeat the process for four or more years.

  • Seek out expertise

Frost seeding is not for everyone, says Demasi. Those who have had good luck at it will be more likely to do it again, and those considering trying it should seek out someone who has had success. “Look at your whole system, consider the risks and the benefits, and find out as much as you can about the process,” says Demasi. Agronomy and seed companies are tremendous resources, and can provide data and advice on which varieties can accomplish producers’ objectives and match their climates.

With the right research, timing and just a little bit of luck, frost seeding can be an inexpensive method to improve forage and hay grounds.

Sometimes you have to make hay – while the snow sparkles.