Grain Sorghum Management

• Plant when soil temperatures reach 60 to 65 degrees Fahrenheit for 3 consecutive days (usually 30 days after last frost).
  • Mid-April to May
  • Late May and early June plantings can lead to decreased yields, though interest in double-cropping later in season is also increasing.
• Marginal to poor ground: 80,000 – 90,000 seeds/acre
  • 4.8 seeds per foot in 30” rows
  • 3.6 seeds per foot in 22” rows
  • 3.3 seeds per foot in 20” rows
• Good ground: 90,000 – 100,000 seeds/acre
  • 5.5 seeds per foot in 30" rows
  • 4.0 seeds per foot in 22" rows
  • 3.6 seeds per foot in 20" rows
• Narrow rows on good ground: 100,000 – 110,000 seeds/acre
  • 4.4 seeds per foot in 22” rows
  • 4.0 seeds per foot in 20” rows
• Planting depth: 1” to 2” on a firm, well-drained seedbed
  • Do not plant over 3 inches deep.
• Advantages of narrow rows
  • Better weed control
  • Increased yields

• Grain sorghum growth and development stages can be estimated using Growing Degree Units, or GDUs (Table 1).

Table 1. Cumulative GDUs for grain sorghum development.

*See Figure 1 below for further explanation.

Figure 1. Grain sorghum growth stages.

• Soil pH should be 5.7 or higher.
• A starter fertilizer is an option, but is a must if planting no-till.
• Apply P and K according to soil test recommendations.
• 120 to 150 pounds of N per acre is adequate to produce maximum yields.
• For heavy clay soils, increase N by 20 to 30 lbs/acre.
• Splitting N is advisable; apply 1/3 at planting and the remainder when plants are in the 4- to 6-leaf stage.
• Head formation takes place after the 8-leaf stage and adequate N is needed at that stage to produce maximum yields.

• Interest in irrigation in grain sorghum management is increasing. Base water applied on water availability, crop growth stage, and yield potential of the crop.
  • See irrigation recommendations by crop growth stage in Table 2.

Table 2. Grain sorghum growth stages, example water use, and suggested inches of irrigation.

• Use of foliar fungicides to manage diseases is increasing in grain sorghum production.
  • Many products are available; base your selection and rate decision on local recommendations and the product label.
• Fusarium head mold and stalk rot can be the most serious disease of grain sorghum.
  • Seed can be infected and cause significant yield loss.
  • Lodging from excess planting rates can create a problem.
  • Look for tolerant and less susceptible hybrids.
• Anthracnose can cause leaf spots, as well as head and stalk rot. Lodging, yield, and quality losses can occur.
  • Management practices include selecting tolerant hybrids, crop rotation, and good fertility.
• Charcoal rot causes problems with heads that fail to fill and plants that lodge later in the growing season.
  • Drought stress will intensify the problem.
  • Management practices include eliminating stresses that are within control, good fertility, and crop rotation.

• Best weed control practices depend on the predominant grassy and broadleaf weeds in your area and field. Base practices on your local extension and herbicide manufacturer guidelines, as indicated on the product label.
  • Grain sorghum weed control programs are usually based around atrazine as the primary active ingredient.

• On full-season grain sorghum, 1 insecticide application may be sufficient, but in a double crop system, 2 applications are common (because worm pressure is much worse).
  • The main insect pests are corn earworms, fall armyworms, sorghum midge, and stinkbugs. Other insects may cause minor damage most years, but major damage on occasion.
  • Proper scouting and timely management is the key to preventing insect feeding damage.

Fall armyworm

Corn earworm

• Grain sorghum reaches maturity between 25% and 30% moisture.
• Typically, the ideal harvest moisture range falls below 20% moisture.
• Grain sorghum must be stored at 13% moisture or below.

• Desiccation is used with most sorghum as a harvest aid to help speed up maturity and control weeds that interfere with harvest.
• Sodium chlorate, applied when grain is less than 25% moisture, is often used as a harvest aid.
• 1 quart of glyphosate is also used in some instances.

• Ciampitti, I.A., Diaz, D.R, and et al. 2014. Kansas Sorghum Management 2014. Kansas State Research & Extension Bulletin MF3046.
• Dahlberg, J and et al. 2013. United Sorghum Program’s West Texas Production Handbook. United Sorghum Checkoff Program.
• Everman, W, Heiniger, R, and et al. 2012. Sorghum 2012 Test Report and Recommendations. NC State University Extension Service.
• Gerik, Thomas and et al. Sorghum Growth and Development. Texas Cooperative Extension, Texas A&M University.