With the recent warmup and lack of snow cover, fields are starting to green up in many places.
As we start shifting from winter to spring, one of the first things on your to-do list should be evaluating the condition of your pastures. If stands are thin, consider frost seeding as an option to thicken your pasture.
It’s important to note that frost seeding, or over-seeding of pastures in general, is not a substitute for poor fertility of pastures. Proper pH and fertility are essential for desirable production. Soil tests should be taken regularly — at least once every three years — and corrective measures taken.
Visit Penn State online for more information on interpreting the results of a soil test.
Although using some type of tillage to renovate pasture has a higher rate of success, using frost seeding is a less expensive option that can be effective if done at the right time and managed properly.
One major factor in frost seeding success is achieving maximum seed-to-soil contact. Often, a pasture that has been aggressively grazed in fall will present a good opportunity for frost seeding. Using a chain drag or running over the field lightly with a disk can open the stand as well. Another way to achieve good seed-to-soil contact is through the trampling effect of livestock.
Frost seeding works as the ground “honeycombs” during this time of year. As temperatures climb to above freezing during the day but drop below freezing at night, the soil opens and closes, working the seed downward into the soil surface.
Early morning frost seeding, before the soil surface begins to thaw, is recommended. If the soil surface is “slimy,” then wait until you get another morning when the soil has frozen again.
Frost-seed to introduce forage legumes
Most often, Penn State Extension recommends using frost seeding to introduce forage legumes into an established stand. Legumes have a much better success rate than grasses. Red clover is the species most recommended for frost seeding because of its seedling vigor and wide tolerance to pH, fertility, drainage and drought.
Obtaining a desirable stand of grass species from frost seeding is much more difficult. Research from the University of Wisconsin (West and Undersander, 1997) shows that perennial ryegrass and orchardgrass exhibit the best establishment success.
If you plan to attempt frost seeding grass, be aware that you will need to make a separate pass with your seeder as grasses will not spread as far as legumes.
How to frost-seed
Frost seeding can be done with any type of broadcast seeder. This can be done by hand, tractor three-point hitch or ATV.
For more information, including best species for frost seeding and seeding rates, read the University of Wisconsin Extension’s Grazier Journal article, “Frost seeding legumes and grasses into pastures.”
Miller and Brackenrich are Penn State Cooperative Extension educators, Miller in agronomy and Brackenrich in field and forage crops.