Crop Planting Guide: Soil Temperature & Germination Back »

Soil Temperature & Seed Germination

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.

Seed germination, one of the key elements of good crop stand, is largely dependent on soil temperature. 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.

S.D. Crop Germination Requirements

Wheat: Among field crops grown in South Dakota (SD), wheat has the lowest soil temperature germination requirement at around 35°F. If the soil temperature is suitable and 30-day forecast shows above freezing temperatures, growers can consider seeding spring wheat early. The earliest planting of spring wheat is suggested for Southeast and Southcentral SD (desired range: March 25th- April 15th), whereas the latest planting is suggested for Northern regions in the state- NW, NC, and NE with desired range of April 8th- April 27th.

Corn & Soybeans: 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 50° F whereas, soybeans require slightly higher temperature at 54°F. However, seeds of these two crops have shown the best germination at warmer temperatures (60°F – 70°F). The earliest suggested planting date for corn is for the Southeast region with a desired range of May 1st- May 15th , and the latest one for the northwest region (desired range: May 12th- May 26th). Similar trends are true for soybean as well.

Other Crops: Other important SD crops such as alfalfa, oat, pea, sorghum, and sunflower require germination soil temperatures of 45°F, 43°F, 42°F, 65°F, and 60°F respectively.


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Photo courtesy of SoilScience.info [CC BY 2.0]

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