Interseeding grass into a thinning alfalfa stand can lengthen its productive life by several years, and late summer can be an excellent time to do it, says Bruce Anderson, University of Nebraska Extension forage specialist.
Orchardgrass is the grass most commonly interseeded into alfalfa, but other grasses like endophyte-free tall fescue, meadow brome, festulolium and wheatgrasses also can be used, says Anderson. In fact, if the field will be used as pasture, he says a mixture of several grasses may be best since it adds diversity to your animals' diet.
Consider interseeding after a mid-August to early September hay harvest if soil moisture is sufficient to start the new seedlings, Anderson suggests. Alfalfa regrows more slowly this time of year so it won’t compete as aggressively with the grasses.
“Still, if your alfalfa is relatively thick, you probably will need to take another cutting in about four weeks, or as soon as the alfalfa starts to form a full canopy,” he says. “This allows sunlight to continue to reach new seedlings below the alfalfa.”
Next spring, if the new grasses seem a little weak, cut hay early to again open the canopy for better light penetration. After that you should be able to hay or rotationally graze as you choose.
“Interseeding grass into existing alfalfa takes timely haying and planting, but both land and livestock will improve with your efforts,” says Anderson.