A report that temperatures dropped to -1 C at Edmonton’s International Airport Sept. 1 caused concern that frost may have damaged nearby late canola crops.
“I haven’t heard any calls yet so let’s hope not,” said Dan Orchard, who works with the Canola Council of Canada.
“Canola can usually take -1 or -2 for an hour. If it’s -3 or -5, if it gets that low, then it’s a problem.… The issue now is making sure it gets swathed before the first major frost.”
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Alberta crops are 10 days to two week behind normal, which has made frost and its potential to downgrade canola a serious concern.
“I’ve seen everything from really good to not so good crops and everything in between,” said Orchard, who has spent the last few weeks walking through canola crops.
“I don’t think there’s really good bumper crops out there.”
It’s not easy to predict when the first killing frost will occur, which determines how long producers should leave canola standing in the field.
Ideally, canola needs to be lying in swaths for three nice days to allow the chlorophyll to leave the seed.
Cool, overcast days don’t allow the seed to be cured and neither do days that are too hot and windy.
Hot, windy weather after swathing may stop chlorophyll from clearing the seed because of a loss of moisture.
Canola specialists recommend swathing during the cool evening hours, at night or early in the morning to allow the seed to dry down at a slower rate to lessen the chance of green seed.
Cutting too early can also reduce yields, said Orchard.
“If you cut at 20 percent seed colour change and it gets hot, drying days, it can lock in the greens and mess up the quality, too.”
“The canola will almost always desiccate and dry up as well.”
Orchard said farmers should talk to their elevator agents about the price difference between canola grades from green seed.
“It usually means a penalty for price, but talk to the elevators and find out what grade price difference is. Sometimes the gap isn’t that wide between the various levels of grading.”
Orchard said a recent period of more summer-like weather in Alberta has helped mature the canola crop, but just glancing at the field can be deceiving.
Some plants have turned colour from sun bleaching, while the seeds haven’t changed.
In other fields, the seeds have started to mature but the plant still looks green.
Warmer weather in Saskatchewan and Manitoba has allowed farmers to get a good start on swathing and combining their canola, said Saskatchewan Agriculture specialist Grant McLean.
“There’s a fair amount of swathing in Saskatchewan. The canola crop in Alberta is still quite vulnerable.”
McLean said the ideal time to swath canola is when 40 to 60 percent of the seed has changed colour in the main stem and average seed moisture is 30 to 35 percent.
“Some of the dilemma farmers face every fall is when do we start swathing.”
Cold temperatures, particularly in Alberta, are a bigger concern. Crops that freeze when immature can produce a higher percentage of green seeds.
It’s especially a concern in northwestern Saskatchewan and Alberta, said McLean, where crops seem to be further behind.
“The big concern is some of those later crops and how risky leaving a crop might be,” he said.
“It is always a challenge to choose a time optimum for swathing. If you choose to swath too early, particularly under high temperature, you lose yield and increase the chance of green kernels.”
