Spring planting guide for South Dakota

David Karki SDSU Extension Agronomy Field Specialist
Farm Forum

Successful crop production to maximize profitability starts at planting. Selecting the best cultivar, preparing seed bed, maintaining optimum crop nutrient needs, and seeding at appropriate rates, date, and time are just a few variables a farmer considers during each planting season. Regardless of where you are located, it is hard to go out and plant on a pre-determined date because of year-to-year weather variability.

This spring, due to consistent precipitation and cooler temperature it certainly looks like we are headed for a late planting, at least for small grains. However, unpredictable weather patterns may suddenly bring us some favorable weather allowing us not to be too late. The earliest planting of spring wheat is suggested for southeast and southcentral South Dakota (desired range: March 25 – April 15), whereas the latest planting is suggested for northern regions in the state with a desired range of April 8 – April 27.

Seed germination, one of the key elements of good crop stand, is largely dependent on soil temperature and overall seed to soil contact. The minimum soil temperatures required by different crops for germination can vary widely, and are reached on different dates each year. Small grains such as wheat, oats, barley, rye, etc. have lower germination temperature requirements than row crops, such as corn and soybeans. Among field crops grown in South Dakota, wheat has the lowest soil temperature germination requirement at around 35F. If the soil temperature is suitable and 30-day forecast shows above freezing temperatures, growers can consider seeding spring wheat early.

Corn and soybean are warm season crops that require fairly high soil temperatures for germination. Corn and soybean seeds can be vulnerable to chilling injury if water in the soil is cold, especially from melting snow. Germination temperature for corn is about 50F whereas, soybeans require slightly higher temperature at 54F. However, seeds of these two crops have shown the best germination at warmer temperatures (60F – 70F). The earliest suggested planting date for corn is for the Southeast region with a desired range of May 1 – May 15, and the latest one for the northwest region (desired range: May 12 – May 26). Similar trends are true for soybean as well. Other important South Dakota crops such as alfalfa, oat, pea, sorghum, and sunflower require germination soil temperatures of 45F, 43F, 42F, 65F, and 60F respectively. Current soil temperatures in South Dakota can be found on https://climate.sdstate.edu/archive/maps/.

Suggested Readings:

• iGrow Corn: Best Management Practices for Corn in South Dakota. South Dakota State University, SDSU Extension, Brookings, S.D.

• iGrow Soybeans: Best Management Practices for Soybean Production. South Dakota State University, SDSU Extension, Brookings, S.D.

• iGrow Wheat: Best Management Practices for Wheat Production. South Dakota State University, SDSU Extension, Brookings, S.D.

• Pathak, T.B., et al. 2012. Soil Temperature: A Guide for Planting Agronomic and Horticulture Crops in Nebraska. University of Nebraska- Lincoln Extension.