Grain Sorghum Planting and Seeding Recommendations

Strong markets are driving Mississippi growers to plant a lot more grain sorghum than what could have been, considering the recent development of Sugarcane aphids as a threat to sorghum production.  Thus, we expect Mississippi growers to plant a considerable acreage to grain sorghum in areas that have a market for this crop. This article will outline some key tips to employ during the planting process to help get your sorghum crop up and on its way to producing a successful crop.

• It is essential to kill weeds with either tillage or a burndown herbicide prior to planting sorghum. Herbicide options to control weeds postemergence are very limited and, of course, there is no broad spectrum herbicide-resistant product available to clean up a mess.

• Soil temperature determines germination rate and needs to be at least 65 degrees F in the morning to ensure quick, reliable emergence. Although sorghum plants look like corn, they require considerably warmer temperature to promote germination, and are more like temperatures needed for cotton. Thus, if it too cold to plant cotton, it is likely to cold to plant sorghum as well.

• We normally recommend a modest population goal of 40,000 – 70,000 plants per acre to optimize productivity of dryland sorghum. This allows sorghum to better tolerate stress common during July and August without sacrificing yield, plant and stalk health. Sorghum is not nearly as responsive as corn to high planting rates and a high density will increase the negative impact of crop stress if you have a droughty season. If you have irrigation potential, you can increase your population goal to 70,000 – 100,000 per acre.

• There is anecdotal evidence that dense sorghum stands may help tolerate Sugarcane aphids. Thus, you may realize some benefit by either planting sorghum in a narrow row pattern or a higher planting rate. If you can plant sorghum in a narrow row pattern, you may realize such benefit without the plant health risks associated with a high planting rate. When evaluating narrow row “planter” options, I strongly prefer using a row crop planter, as opposed to a grain drill, in order to achieve better seeding precision, seeding depth and control of seeding rate. Growing an exceptionally high plant population increases the likelihood of yield loss, stalk rots, and lodging associated with stress, particularly in dryland fields.

• Sorghum should be generally be planted 1 ¼ – 1 ½ inches deep depending on soil texture and soil moisture. Deeper depth is fine for sandy soils, particularly if soil moisture is short.

• Considering we have plenty of glyphosate tolerant pigweed in many fields where sorghum will be planted and limited herbicide options for postemergence use, you better use a strong residual herbicide program to control weeds. Lexar is the benchmark for sorghum weed control. It contains three diverse modes of action to attack weeds and combat resistance. The mesotrione component is a new, unique mode of action, and is critically helpful for controlling glyphosate-resistant pigweed and morningglories.