Alternative Forage Options: Tips for Seeding Warm Season Annuals

With turning the calendar to June, now is the time to be seeding warm-season annual forages like sorghum, sorghum-sudangrass, sudangrass, millets, and teff. These forages can help to fill in the gap with the summer slump or provide some extra forage when your perennial forage supply may be short. Below are some helpful reminders on establishing and utilizing warm season annual forages.

• Seeding Window: Four-inch soil temperatures should consistently be 60^oF or warmer before seeding warm-season annual forages, which is why it’s recommended waiting until the first of June to seed. Typically, the recommended window to seed warm season annual forages is sometime between the first of June through early July. To maximize yield potential, we recommend seeding early.
   
• Species Selection: When deciding which species to plant, consider how you plan to use that forage. Do you plan to graze, hay, or chop? Some species are better suited for grazing or silage compared to baling. While most are multi-cut or multi-graze or cut, several species, like foxtail millet or German millet, are single use only. Check out the table below to see what species are better suited for grazing or silage compared to baling as well if species are multi or single cut.
  

  Species	Dry hay	Silage	Grazing	Single or Multi Cut	Prussic Acid Concern
  Forage Sorghum		x	x	Multi	x
  Sorghum-sudan		x	x	Multi	x
  Sudangrass	Possible	x	x	Multi	x
  Teff	Possible	x	Sensitive	Multi
  Foxtail Millet	x	x	x	Single
  Japanese Millet	x	x	x	Multi
  German Millet	x		x	Single
  Pearl Millet		x	x	Multi

• Soil Moisture Conditions: One of the concerns this year with seeding annual forages is the drier soil moisture conditions across the state and lack of rain in the forecast. Except for teff, which should be seeded very shallow at 1/8 to ¼” deep, other warm-season annual forage species should be seeded between ½ to 1” deep. If soil conditions are dry, that seed will remain and will be able to take advantage of moisture when the next rain comes. However, the other risk is getting enough moisture to get the seed to germinate, but not enough to help keep that plant going. Unfortunately, we don’t have a crystal ball to tell us what to expect.
   
• Seeding Method: Good seed-to-soil contact is key to help with establishment. The preferred method of seeding would be with a drill, but it’s important to make sure that the drill is set-up correctly to achieve ideal seed depth and rates. While broadcasting may provide some challenges with stand establishment, going over the field with a cultipacker can help improve establishment.
   
• Using for Forage: Typically, our warm season annual forages are ready for use within 50 days of emergence. Pay attention to how short you graze or harvest annual forages as this can impact how much forage you have available with the second or third time around. As a rule of thumb, leave about a 6-inch stubble height to help maximize regrowth.If harvesting for dry hay, use of a mower-conditioner is ideal as it will help with speed up dry down. A disc mower and rake work OK, but it does take longer to get the forage to dry down. Another option would be to wet wrap the forage.

Assuming we have the moisture to get them started and going, warm season annual forages can be a great option to help fill in that slump when our perennial forages slow down as well as if we are short on forages, especially with the drier conditions the last couple of years.

Two resources with additional information on warm season annual forages are the ISU publication ICB 0136 “Alternative Annual Forages” and the UNL publication G2183 “Summer Annual Forage Grasses”.

A special thanks to Aaron Saeugling, Meaghan Anderson, Denise Schwab, Erika Lundy, and Beth Reynolds for reviewing.