This spring’s wet weather delayed planting of some of our May forages. Combined with a cool June that kept soil temperatures below optimal for many warm-season annual grasses, there have been some questions about late-planting options for forage crops.
The success of early-planted warm-season annual grasses (sudangrass, sorghum-sudangrass, millet, and teff) is typically determined by soil temperature, and soils should be above 60-65* F before you begin planting. Later in the summer, establishment success is more moisture-dependent. Yields can also be reduced for late-planted crops, since they’ll have a reduced growing season.
We don’t have a lot of recent data on exact cut-off dates for warm-season annual forage establishment in Ohio. The Ohio Agronomy Guide recommends that plantings continue through late-June in northern Ohio, and that plantings can continue through mid-July in southern Ohio. Anecdotally, we’ve seen successful sorghum-sudangrass establishment into July throughout the state as long as adequate soil moisture is available during planting.
If you’re considering a late planting of warm-season annual grasses on your farm, pay attention to ground prep. No-till establishment is certainly possible in many years, but the heavy, intense rains that covered most of Ohio in June has caused both crusting and extensive weed pressure in some fields. Tillage can help manage both crusting and weeds, although it may also reduce soil moisture. Plant quickly after tillage is completed to reduce these concerns.
Regardless of whether you choose to till or not, proper drill set up will help optimize establishment. Teff should be planted 1/8-1/4 inch deep, and must be drilled, not broadcast. Species like millet and sorghum-sudangrass should be planted ½-1 inch deep. These larger-seeded warm-season annual grasses can also be broadcast and harrowed in, but fields established this way will be more sensitive to dry weather in the week or two following planting. Make sure to increase your seeding rate by about 1/3 for broadcast plantings as compared to drill plantings, and learn more about seeding rate recommendations in the Ohio Agronomy Guide.
In short, you still have a few weeks to get warm-season annual grasses planted. Pay attention to weeds and soil moisture to optimize establishment.
Don’t have an Ohio Agronomy Guide? Call your local extension office or get one here: https://extensionpubs.osu.edu/ohio-agronomy-guide-16th-edition-pdf/