The AgriPost
May 29, 2026
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Cool Spring Puts Soybean Planting Decisions Under the Microscope By Harry Siemens Manitoba soybean growers can begin planting when field conditions are suitable, but Dennis Lange says this spring’s cool, uneven weather makes patience, risk assessment and stand checks especially important. Lange, provincial pulse and soybean specialist with Manitoba Agriculture, told this week’s Manitoba Agriculture CropTalk that growers face a familiar but challenging question: when is it safe to seed soybeans? He said the decision depends on soil temperature, calendar date, the 24-hour forecast, field conditions and each farmer’s personal risk tolerance. “It’s been a very strange spring,” Lange said, noting Manitoba recently swung from -4 C in the morning to +12 C within a short period. “It makes it kind of difficult
Dusty spring conditions show the challenge Manitoba soybean growers face when deciding whether to roll fields after planting. Dennis Lange, provincial pulse and soybean specialist with Manitoba Agriculture, told CropTalk that dry soils, strong winds and soil movement may make post-emergent rolling a better option in some fields.
Post-emergent rolling can help press stones into the soil and smooth soybean fields, but timing matters. Dennis Lange said growers should roll only on warm afternoons, avoid the hook stage, and check for broken plants to make sure the stand remains strong.
for growers, considering we’re planting a warm-season crop that requires more heat to germinate.” Lange said soybeans can take 24 to 35 days to emerge when soil temperatures range between 6 C and 12 C.
slow start. “They’re probably going in the ground treated, but it’s going to take a couple of weeks, maybe three weeks, to get those beans out of the ground and establish a good stand,” he said.
When soils warm to 14 C to 22 C, emergence can occur in four to 16 days. Manitoba has not yet reached those consistently warmer soil temperatures in many fields. That means growers who seed now should expect a
Photos by Harry Siemens
Lange urged growers to pay close attention to the first 12 to 24 hours after planting, when soybean seed absorbs water rapidly. If cold water enters the seed during that early imbibition phase, chilling injury can reduce emer-
gence or weaken the stand. Lower-quality seed, dry seed or seed with a damaged coat faces higher risk. Lange said growers should handle those seed lots carefully and use proper seed treatment, especially in cold soils. Early planting also increases the risk of frost after emergence. Lange said temperatures below 0 C can damage young soybeans, while temperatures below -2 C for more than four hours can be lethal. Heavy residue can increase frost risk, while heavier-textured soils may store more heat and offer some protection. Soybeans have three growing points: the main shoot and two axillary buds at the base of the cotyledons. If frost only clips the top growth, plants may regrow. If freezing damage extends below the cotyledons, those Continued on Page 2...