Overseeding warm-season perennial grasses with cool-season legumes provides several benefits: Grazing can begin 4 to 6 weeks earlier than spring grazing, reducing the winter feeding period. Legumes typically have a higher nutritional value than most grasses. Legumes fix nitrogen from the atmosphere and make it available to the pasture system. A good legume variety can help control spring weeds by competing for space, water, sunlight and nutrients.
Three methods for establishing cool-season annual grasses include planting in a prepared seed bed, the light pinching method and over-seeding or seeding in undisturbed soil. Growing annual grasses in a prepared nursery involves destroying existing plants by scraping up the ground and then rolling (packing) it to provide a stable planting surface and retain moisture. Plant cool-season grasses in prepared seed beds from mid-September to early October. It is best to plant just before rain. For best results, have the soil tested to evaluate the need for limestone, nitrogen, phosphorus, potassium or other nutrients. Phosphorus and/or potash fertilizer can be applied before or during planting. Nitrogen fertilizers are usually applied separately and, depending on soil test recommendations, may require one to three divided applications at a rate of 50 to 60 pounds of nitrogen per acre. Delay the initial nitrogen application until after the grass has emerged.
The light pinching method is used on bermudagrass and bahia grass stands and involves grazing, harvesting or mowing the pasture to less than 4 inches, then turning the soil 1 to 2 inches deep. This reduces competition from warm-season grass and provides loose soil to cover the seeds. For this method, plant cool-season annual grasses 4 to 6 weeks before the average first killing frost, which usually occurs in November. Plant the seeds using a drill or broadcaster and then use a type of pasture tow to cover the seeds. Apply phosphorus and potash according to soil test recommendations. It can be applied at or before planting time, or 2 to 3 weeks after the grass emerges. Delay the initial application of nitrogen fertilizer until after the cool-season grass is established and cold temperatures have reduced warm-season grass growth. The need for nitrogen fertilization depends on the soil test and can be divided into one to three applications of 50 to 60 pounds of nitrogen per acre.
Overseeding or sowing seeds in undisturbed sod requires only that the warm-season grass be grazed, mowed or mowed to a height of less than 4 inches. Large-scale casting on undisturbed grass is usually limited to annual ryegrass and small-seeded clovers such as ball or white clover. Use a lawn seeder (no-till) or fertilizer truck if you are growing small grains. If broadcasting cool-season grasses, increase seeding rates by 25 to 30 percent. Planting time for over-seeding/seeding is several weeks later than other methods to reduce competition from warm season grasses.
Apply nitrogen fertilizers only after cool-season grass is established and low temperatures have reduced warm-season grass growth. Nitrogen fertilization can be divided into one to three applications of 50 to 60 pounds of nitrogen per acre. Apply phosphorus and potash fertilizer according to soil test recommendations. Cool-season annual grasses are best for young growing animals such as stock heifers, replacement heifers, first calf calves, and creeping grazing heifers.
For fall-calving cows, limit grazing to 2 hours daily or 4 hours every other day during the fall and winter as a protein and energy supplement. As the growth rate increases in early spring, increase the number of hours per day in the pasture. Can be used for cows born in the fall or winter. It should not be used for dry and mature cows due to its high production cost.
For more information on this or any other agricultural topic, please call the Hopkins County Extension Office at 903-885-3443 or email me at (email protected).