May 25, 2007

Once corn, beans, milo, and other crops are planted, it's natural to want to plant your summer annual forage grasses, but don't rush. Planting too early can be bad for these crops.

Summer annual forage crops — like sudangrass, millets, cane, and sorghum-sudan hybrids — are hot weather crops that can be injured or even permanently stunted by cool weather.

Wait to plant summer annual forage grasses until soil temperature remains permanently above 60°F or for millets, 65-70°F. This is late May at the earliest and early June in many cases. Air temperature must remain warm, even at night. If either soil or air temperature gets too cold, the summer annual grass can be stunted permanently, no matter how nice the growing conditions are.

True sudangrass might tolerate cool temperatures better than other summer grasses. If soil stays above 55°F and air temperature doesn't drop below 40°F, sudangrass eventually will recover from the cold stress. On the other hand, millets and some forage sorghums will never snap out of the stress caused by a 45°F or 50°F night.

The few days you gain from early planting for earlier grazing is small compared to the risk of losing most of the plant's growth potential.

Bruce Anderson
Extension Forage Specialist