Overseeding Winter Annuals: How do you overseed warm season perennial grasses with winter annuals? Do you recommend overseeding cool-season perennial grasses?

The use of winter annual forages (ie. rye, wheat, oats, and annual ryegrass) is now common practice in Alabama. Many producers plant into prepared seedbeds and use the forage for temporary grazing , while others plant for harvested/stored feed production. Also, a common practice is to overseed warm season perennial grasses (i.e bermudagrass or bahiagrass) to maximize land utilization during the cooler months when summer grasses are dormant.

When done correctly, overseeding of winter annuals can result in a dependable source of forage during the cooler months. Following a few key steps to overseeding will help to increase your success:

1. Apply fertilizer and lime based on soil test recommendations prior to planting.
2. Proper seeding time: North AL (Oct. 1st-15th), Central AL (Oct. 15th-30th), South AL (Nov. 1-15th)
3. Remove as much excess forage as possible from the remaining summer grass through grazing, clipping, or burning (typically a 1 inch stubble height is recommended).
* Light tillage may be acceptable when working with an older bahiagrass stand with a thick thatch that is difficult to remove.
4. For more precise seed placement, use a no-till drill or cultipacker seeder for best results.
*If broadcasting, increased seeding rate by 25-30%
5. Plant small grain seed 1 - 1 1/2 in deep in moist soils. Plant annual ryegrass no deeper than 1/2 in.
*If planting a small grain/ryegrass mixture - broadcast annual ryegrass seed and then drill grain. *Broadcasting of annual clovers is acceptable

Remember: Remove winter annual forage before spring green-up of warm-season perennial grasses to decrease chances of stand depletion.

Overseeding Winter Annuals into Cool-Season Perennial Grasses: Taking the above idea and applying it to cool-season perennial forages is not recommended. Research from the University of Tennessee evaluated overseeding tall fescue with wheat and ryegrass. The results indicated that fall fertilization of tall fescue and the exclusion of overseeding winter annuals still provided the highest yield in the resultant spring with both early and late harvesting of the forage. The addition of winter annual grasses to cool season perennial grasses did not improve forage quality or extend the grazing season.

Remember: When planting forage mixtures the goal is to plant species that are complimentary to one another. Warm season perennial grasses and cool season annual grasses and legumes have opposite growth cycles, thus decreasing the competition affect for water, nutrients, and sunlight. Tall fescue and annual ryegrass are both cool season forages that achieve much of their growth during the same time of year. With two productive grasses growing in the same area, increased competitiveness will eventually result in lower yields and potential stand loss of the perennial forage.

*Prepared by Jennifer M. Johnson, Ph.D, Extension Agronomist, Alabama Cooperative Extension System