It is October and it is time to think about overseeding your pastures. Warm season perennial forage crops like bermudagrass and bahiagrass supply forage for about five or six months. Overseeding these pastures with winter annuals can provide an additional 80 to 100 days of high quality forage. Fall overseeding usually does not provide fall and early winter grazing. Quality of forage increases rapidly rapidly from overseeded crops in mid-winter and early spring.. Small grains such as wheat, oats and rye produce more forage early in the season. This is especially important when forage needs are critical. Oats may be planted earlier than other small grains. Rye has the best cold tolerance. Clovers can contribute nitrogen to your perennial pastures. Be sure to plant clovers in a well drained situation because clovers do not tolerate wet conditions. Clovers can be planted with small grains or ryegrass. Crimson or Arrowleaf clovers are really good choices for winter annual mixes. The clovers can also increase total forage production and extend the grazing further in the spring.
Overseeding has not always been successful. Some failures are caused by failure to remove growth of summer crop, failure to get good seed to soil contact, and lack of plant nutrients. The accumulated growth should be removed and this can be removed by close grazing. . Research has been shown that it is preferable to a height of 1 inch or less if possible. This is especially important with small seeded forage species.
Producers have to be aware that growth of summer grasses may be delayed by the winter annuals if a dense growth of the winter annual is allowed to accumulate in late spring. If surplus occurs, it should be harvested for hay to permit near normal development of the summer grasses
Seed to soil contact is very important in overseeding pastures. When there is no erosion hazard, light disking or harrowing will often increase the chances of getting good stands of overseeded annuals, particularly if the stubble is higher than one inch.
Planting depth is very important. As a rule of thumb, a given type of seed should not be planted deeper than 8 times its diameter.
Growth activity of the warm season grass should be used as a guide for planting rather than calendar year. Overseeding must be done after summer grasses become dormant or near dormant or about the time of frost. If the crop is overseeded too early then crowding out will occur and a poor stand will result.
Fertility is also another concern with overseeding pastures. Phosphorous and potassium should be applied at or near planting time as recommended by a soil test. If you are planting a grass-legume mixture, apply 100 pounds of nitrogen per acre in the fall and another 50 pounds of nitrogen in mid winter. If the clover comprises 30 percent of the stand in spring, no additional nitrogen is needed. If only annual grasses are overseeded, apply 150 pounds of nitrogen in three applications, 50 pounds of nitrogen in fall, 50 pounds of nitrogen per acre in winter and another 50 pounds of nitrogen per acre in spring. It is probably best to delay fall nitrogen applications until seedlings have emerged. If you are overseeding with just clovers then no nitrogen is needed.
Soil pH is very important, especially with clovers. The general recommendation for good winter annual forage production is that the soil pH be in the range of 6.0 to 6.5.