COLUMBUS, Ohio – Frost seeding is one of the many tools a farmer can use to establish more or different forages into an existing pasture or field. It is relatively inexpensive. It works well for clovers; many grass pastures or fields can benefit from having more legumes.

“There are a lot of tools and a range of technology levels that allow you to get seed onto a field,” said Dr. Emma Matcham, Ohio State University assistant professor of integrated forage systems. “Frost seeding has a narrow window of time that you can do it. In Ohio, farmers usually frost seed sometime in February because they want the soils to go through a few freeze/thaw cycles after the seed is put on the field but before that spring warmup.”

Freeze/thaw cycles open the soil surfaces in what is called “honeycombing,” where the soil surface changes shape a few times, Matcham said. That allows the seed to come in contact with the soil and will allow it to germinate once the soil has warmed up.

“The seeds can be spread on the soil surface many different ways,” Matcham said. “The most common is probably a spinner spreader on the back of an all-terrain vehicle. You can also use a handheld spinner spreader. A drone would be one of the higher tech options.

“One of the really low-tech options that works well for people, if they’re OK with slightly less even distribution of seed, I have seen people hand spread seed while they’re out walking the fields in the winter,” she said. “Or they can put it in a backpack with some holes and play fetch with their border collie.”

The timing is the most important thing, she said. The soil must go through some freeze/thaw cycles, and you can’t spread seed on 6 to 8 inches of snow. If there is a lot of snow on the ground and there is a sudden warmup, that seed is going to drain off into the ditches instead of straying on the field.

Clovers are the most common species for frost seeding. Birdsfoot trefoil is another legume option, annual ryegrass, orchard grass, and some other grasses can be established this way. But plant establishment from frost seeding is usually higher for clovers than other species.

A farmer can frost seed into almost anything but there are some things they can do before winter that will improve success, that is, the amount of seed that establishes and becomes a plant in spring. One of those things is grazing the field a little lower in fall so there is soil that the seed can make contact with. In thick growth it will be hard for the seed to make its way down to the soil surface and then for the emerging plant to have enough light to grow.

“We don’t recommend this in really thick pasture stands that have a lot of above ground growth,” Matcham said. “Also, the people who frost-seed tend not to frost-seed all of their acres because you don’t want to graze a freshly frost-seeded pasture. We want to give newly established plants some time to grow.”

So, farmers don’t want to frost-seed the field they use for turnout first thing in the spring. The plants should have a good root system before animals are turned into it for grazing. Also, don’t spread nitrogen on a field that is freshly frost seeded with legumes because those legumes need to nodulate and start fixing nitrogen.