Guenther: How cold is too cold for soil at seeding?

A field awaits action near Livelong, Sask., about 110 km east of Lloydminster. (Lisa Guenther photo)

Spring snow may have unleashed a litany of complaints among Saskatchewan residents — but has also brought relief to parched soils in the province’s northwest.

Errin Tollefson, an agronomist with Cavalier Agrow at Medstead, Sask., about 170 km west of Prince Albert, said last fall was the driest she’s seen in her 10 years of soil testing in the area.

“I was pretty concerned that we were going to be heading into a dry, disastrous spring but soil moistures are excellent,” she said in an interview, adding moisture extends three feet into the soil profile.

And recent spring snow isn’t likely to delay seeding in the area.

“In terms of soil temperature, we’re ready to get moving,” Tollefson said. Soil temperatures in the Medstead area are averaging about 5 C, she added.

If local farmers start seeding next Monday, “we’d be pretty much right on par for normal.”

Cool soils

Dave Vanthuyne, an agronomist with DuPont Pioneer at Watrous, Sask., about 100 km southeast of Saskatoon, recommends measuring soil temperature for two or three days at a depth of one and a half inches.

Temperature should be taken between 8:30 a.m. and 4:30 p.m., he wrote in an email.

“My rule of thumb is when average soil temp is 5 C and long-range forecast is favourable, then that’s my green light to go,” Vanthuyne said.

Canola growers wanting rapid germination and emergence will want to target an average soil temperature of at least 8 C or higher, he added.

Canola will absorb water and germinate in soils as cool as 2 C, Vanthuyne said, but the cold will delay emergence and could lead to poor stands and uneven maturity.

Farmers can’t always wait for soil to warm, however.

“If it’s colder and it’s the middle of May and guys have lots of acres to do, we’ve got to get at ‘er,” said Tollefson.


Germinating seed is exposed to disease and insects for a longer period of time in cool soils, Tollefson said, so she recommends a seed treatment when planting in cool soil.

BASF Canada also recommends a seed treatment to protect seedlings, especially in cold soil.

“By using a seed treatment with plant health benefits, crops can get off to a good start in spring,” Russell Trischuk, technical marketing specialist for BASF Canada, said in a release. “Having a more vigorous, robust seedling will obviously lead to better plant health down the road.”

Vanthuyne suggested bumping seeding rates by at least a half-pound when soil temperatures dip below 8 C, regardless of seeding date.

Tollefson said she doesn’t always recommend bumping canola seeding rates in cool soils, but “if the soil is significantly cooler than 5 C, you could consider bumping up your (seeding) rate as a risk management tool.”

Now is a good time to scout for emerging weeds, too, she said.

“Lots of the weeds have germinated but they’re still sitting under a thatch layer.”

By waiting until the weeds pop through the thatch, “you’ll get a much bigger benefit from your spraying operation.”

— Lisa Guenther is a field editor for Grainews at Livelong, Sask. Follow her on Twitter at @LtoG. Errin Tollefson, David Vanthuyne and Russell Trischuk can be followed on Twitter also at @AgrowErrin, @AgbyDave and @sciencefax.



About the author


Field Editor

Lisa Guenther

Lisa Guenther is field editor for Grainews based at Livelong, Sask. You can follow her on Twitter @LtoG.



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