The following is from Grazing Bites and is used with permission.
by Victor Shelton, NRCS State Agronomist/Grazing Specialist
Frost seeding is certainly one of the least expensive ways to enhance the stand of legumes in your pastures. It is basically the process of broadcasting the legume seed onto the soil surface during the winter dormant months. For the most part, I usually say the ideal time is somewhere between Christmas and Valentine’s Day. If I really had my choosing, I’d wait until there is a light snow on the ground and then do the sowing. The snow serves two good purposes. One, it helps “catch” the seed and transport it to the ground and two, it serves as a great marker for the tractor or ATV.
Frost seeding relies on the freezing-thawing action of the soil, which is honeycombing the soil surface with ice crystals. This causes the soil surface to expand and contract, allowing the small seed to find a route into the ground. During warmer winters, you might not always get enough action and if you don’t get good seed-to-soil contact and the seed does not get covered; then it is less likely to survive. I doubt that will be the problem this year. Too often, when left lying on the soil surface, the sun can warm the ground and seed enough to initiate germination. It has little chance of surviving if this happens before the occurrence of another killing freeze. The seed that is protected by the soil will not be as likely to be impacted by the sun and is more likely to wait until the proper time period to germinate.
Competition is probably your next worst enemy. Now, I would hope that most would not consider broadcast seeding or frost seeding into a heavy stand of grass, but I have seen it done, usually with less success. If you know you are going to be frost seeding legumes into a pasture then I would recommend waiting until after the forage has become dormant and then graze it down to about 3-4 inches to remove any excess growth (not a problem now) to allow the seed to find its way to the soil surface and wait for that freezing action. Grazing closer to the soil surface also helps to depress early spring growth of the grass which will give the legume seedling a fighting chance. Now that reminds me to mention, don’t hit those newly seeded fields with nitrogen in the spring either. All this does is to promote the grass growth in the sward and reduce those new legume seedlings’ chances. They won’t have the root base or energy stored up to compete with established grass, especially with a boost of nitrogen!
In closing today, you get three things usually for nothing: air, sunlight and water. Pretty much everything else you will pay for one way or another. All three are needed to grow forage. Maximize forage production, be as efficient as possible in grazing and maintaining it, and it will have a positive impact on your bottom line.
Remember, it’s not about maximizing a grazing event, but maximizing a grazing season! Keep on grazing!
For more information, check out these articles:
https://ciscoforage.com/blog/improve-pastures-by-frost-seeding-clover
https://ciscoforage.com/blog/consider-gallant-red-clover-when-frost-seeding
More pasture information and past issues of Grazing Bites are available at https://www.nrcs.usda.gov/wps/portal/nrcs/in/technical/landuse/pasture/