How rapeseed is grown and harvested

Canola is rapeseed that was bred to have low erucic acid, and the name was a trademark before it became a word.

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The short version

Rapeseed goes in during autumn across most of Europe and Asia and sits through winter as a leaf rosette, while Canadian crops are sown in spring. Pods ripen over 6 to 8 weeks, bottom of the plant first. Many growers cut the crop into windrows at 30 to 60% seed color change, then combine it days later.

Sow in autumn or spring

Winter varieties go in during autumn and need the cold to flower. Spring types, grown in Canada, northern Europe and Australia, cannot survive winter and start stem growth right after germination. In Europe the winter crop often rotates with wheat and barley every three to four years, to limit pests and disease.
Flower and fill the pods

Flowering starts at the lowest bud and works upward. Pods grow 5 to 10 cm long and ripen from green to brown over 6 to 8 weeks, each holding a row of hard black seeds 1.5 to 3 mm across.

6 to 8 weeks of pod ripening
Check seed color

Growers open main-stem pods from around the field, since hilltops ripen ahead of low spots. At 35 to 40% moisture seeds turn from green to yellow or brown. The best time to cut is at 30 to 60% color change, and seed stops filling once the crop is down.
Cut into windrows

A swather lays the crop in rows on the stubble, which cuts shattering and can speed dry-down by up to 10 days. Draper-belt machines do less damage than augers, and some growers roll the swath so wind cannot shift it. Others skip this step and combine the standing crop directly.
Combine the dry swaths

Combining waits until seed drops below 10% moisture, normally 5 to 10 days after swathing. Rubber fingers lift the row gently. The cylinder turns at about 60 percent of cereal speed, and cleaning leans on shaking over wind, since the seed is light enough to blow out the back.

under 10% seed moisture

End of the lineRapeseed Next it goes into vegetable oil.

Worth repeating

Canadian scientists launched a marketing campaign in 1973 for what became canola, trademarked in 1978 by the Canola Council of Canada.
World rapeseed production rose sixfold between 1975 and 2007.
The word rape comes from the Latin for turnip, rapa.