Improving pastures with late winter frost seedings of certain legumes and grasses can be successful. If the planning and preparation
Frost seeding of clovers, birdsfoot trefoils, and some grasses such as annual and perennial ryegrass can be a very economical way to improve pasture forage growth and nutritional quality. Frost seeding is usually performed in late winter typically 40 to 50 days before grass growth begins in the spring. Frost seeding works best on clay and loam soils that experience soil movement with the freezing and thawing action that takes place that time of year. Part of the popularity of frost seeding is its ease of implementation and low cost. Producers have to simply buy the seed, broadcast the seed and watch it grow. There is no spraying, tillage, stone picking, nor loss of grazing for a summer that comes with re-seeding a new pasture. And in many cases the end result can be almost as good as a new seeding.
The common practice is to add a red or white clover seeding to a pasture when the legume percentage in the pasture is less than 40 percent. The existing grass pasture is not tilled or sprayed, just the clover seed is broadcast over
To give the frost seeded plants a better chance in the spring, over-grazing the grass stand in the fall is advised. When frost seeds are planned, it is the one time that Michigan State University Extension forage educators will advise you to weaken, or hurt the pasture stand in the fall before seeding.
Over-grazing does two things to help the success of the frost seeding. First it reduces the root food reserves of the pasture stand that will cause the grasses to be less aggressive in the spring. Secondly, by taking the grasses right down to two inches of stubble in late fall it removes the thatch layer on the soil surface, exposing more soil, which will lead to better soil-to-seed contact in the spring. Erosion is a slight risk as a result of this
Frost seedings are beneficial when they work. To shift the odds of success more in your favor, weaken the pasture stands this fall that you are planning to frost seed.
Source: Michigan State University