Grain sorghum population should be adjusted in accordance with a realistic yield goal or probable yield. If 15 percent of the plants from the viable sorghum seeds planted will be lost before harvest, the number of seeds required per acre will be about 15 percent more than 47,600, or 54,700 seeds per acre. Early plantings have a greater chance for reduced emergence, so rates need to be increased. In Nebraska, it is better to be on the low side of the desired population rather than the high side. Under heat and drought stress, plants at a lower population have more soil volume from which to draw water and can survive better than a thicker stand.
High populations tend to force the crop into stress more quickly when moisture supply is limited.
Pay attention to the amount of moisture that is in the soil profile at planting time before determining the planting rate. Sorghum stands of 20,000 have produced yields of 80 bushel per acre. It is generally thought unwise to replant sorghum if the present stand is approximately 20,000 per acre or more. The size of grain sorghum seed varies among hybrids and from situation to situation, depending on growing conditions. Some lots will have 12,000 seeds or less per pound and others 16,000 seeds or more.