Improve Your Clover Overseeding Success
Crop and Soil Environmental News, February 1997
Extension Specialist, Forages
Seeding clovers into poor producing or grass-dominated pastures by broadcasting seed in late winter is certainly nothing new. Cattleman have been overseeding or "frost seeding" for years but have often been faced with highly variable results. Overseeding involves some risks, not the least of which is precipitation. While we can't do much about controlling the weather, there are some key management moves that can increase the likelihood of getting a good clover stand by overseeding.
Quality seed and adequate soil pH, P, and K levels are certainly critical to overseeding success. However, I suspect that many overseeding failures are due to inadequate control of grass growth both before and during clover establishment. The best strategy is to overgraze the field to be overseeded during the previous fall. This intentional abuse will provide openings in the sod for clover emergence and set back the sod's vigor the next spring. It's fine, in fact probably beneficial, to leave cattle in the pasture for a few days after overseeding if the field isn't excessively wet. Their hoof action (moderate "pugging") will assist natural late winter freezing and thawing to work the broadcast seed to a desirable depth for germination.
Cattle should be removed from the field before clover seedlings emerge but should be brought back to graze down the grasses when they are about 10 to 14 inches high. This should be a quick graze down to just above the clover seedlings which should be a couple of inches tall by now. Graze for no more than a few days and delay if conditions are extremely wet. Don't worry about damaging a few clover seedlings at this time. The few seedlings lost during this grazing are far less than the number of seedlings that would be lost to competition for light and moisture if established grasses are not grazed.
This "flash" grazing will likely have to be done again in 3 to 4 weeks. Rotational grazing systems provide a natural setup for this type of management if a few paddocks are overseeded at a time. If the overseeded area is to be cut for hay, it should be overseeded only with red clover and hayed as early as possible.
Although herbicides enable us to suppress or kill the sod more easily, they take away useable forage. Keeping grass growth in check by flash grazing as overseeded clovers become established provides us with some grazing while improving the likelihood of successful clover establishment.
Virginia Cooperative Extension
Visit Virginia Cooperative Extension