One of the most cost-effective, low energy ways to improve the quality and yield of grass pastures is by frost seeding legumes. The time for frost seeding in northern Illinois is about a month away.

What is frost seeding? Frost seeding is the broadcast, surface placement of seed in late winter, early spring on frozen ground. Sometimes referred to as overseeding, this method is dependent upon the freezing and thawing action of soil, a late snowfall, plus early spring rains to provide soil coverage. Frost seeding should be done when the soil freezes at night and thaws on the surface during the day. Frost seeding has limited success on sandy soil and in years with abnormally dry springs, and early summer weather.

Since there may not be uniform seed germination and emergence, frost seeding is not suggested for hay fields, but is an acceptable method for pasture improvement. The practice works well on steeply sloping sites; but should not be done on snow-covered sloping ground.

What legume species are best suited for frost seeding? Experience and research has shown that medium red clover is the easiest to establish. Red clover has good seedling vigor, shade tolerance, and is more cold tolerant than alfalfa. A second option

would be white clover, especially for wetter, poorly drained soil. Frost seeded legumes

need to be properly inoculated and the soil pH needs to be in the acceptable range. The degree of soil drainage will also affect the choice of legumes.

Better legume stands are obtained when frost seeding into a bunchgrass (for example, orchardgrass and tall fescue) sod or into thin sods of Kentucky bluegrass or smooth bromegrass. Frost seeding is dependent upon the seed reaching the soil surface. One must also reduce the plant competition for the frost-seeded legume. This can be accomplished by grazing the pasture down, or reducing the residual growth, in the fall and early winter.

Frost-seeded pastures need to be grazed regularly in the spring and summer to permit sunlight to penetrate the plant canopy so the legume can grow and develop. But, livestock should not be allowed to closely graze the new seedlings until they are established.

What seeding rate should be used? If one frost seeds red clover every year, about 4 to 6 pounds per acre would be suggested. If seeding every other year, consider 8 to 10 pounds per acre. Some producers say that frost seeding yearly builds up the seed bank in the soil. White clover should be seeded at 2 to 3 pounds per acre by itself, or 1 to 2 pounds per acre if part of a seed mixture.

Cyclone-type seeders that mount onto ATV's or tractor 3-point hitches are commonly used. Be sure to determine the seeding width for each seed type or mixture.

With proper grazing management and cooperation from Mother Nature, frost seeding is an economical way to improve the quality and quantity of pastures.