Agricultural News
Getting Winter Canola Established Before Winter Dormancy- How Late is Too Late?
Wed, 05 Oct 2011 10:15:44 CDT
Dry seedbed conditions continue to exist in many parts of Oklahoma as we approach the tail-end of the canola planting window. However, we still have time to plant and have a good chance to establish winter hardy canola stands. Canola plants require an adequate amount of time (4-6 weeks) to develop leaf area and begin photosynthesis to enable carbohydrate storage in roots.
Ideally, a large tap root (1/2-inch diameter) would provide adequate carbohydrate reserves in the root to help the plant survive. Winter canola will tolerate freezing temperature for short periods of time as long as the temperature does not get below 25oF. Leaf margins may be hurt but as long as the crown remains unharmed the plant is alive and will begin re-growth as soon as temperatures warm up. When dormancy occurs, canola can easily tolerate freezing temperatures for long periods of time.
Maximum winter hardiness in canola has been observed when plants have 7-8 true leaves and the canopy height is about 10 inches. True leaves are defined as leaves that emerge from the growing point (crown) after the two cotyledon leaves emerge from the soil.
A new leaf will appear every 4-7 days during the fall before winter dormancy. Even emergence with winter canola is not as important as with crops such as corn and sorghum. After canola re-growth begins in the spring plants should look similar. Winter survival is dependent in a large part upon carbohydrates stored in the plant's roots.
So the question remains how late is too late to plant canola? Final planting date without penalty for insurance is listed as October 10 for Oklahoma. However, you can plant up to 5 days later than the 10th but you get penalized with a 3% yield reduction per day. In the southern part of the state there have been years when planting dates have been later than Oct. 15th but the risk of winter kill does increase the later the planting date is after the 15th.
Winter survival all depends on the growing conditions between planting and dormancy. Ideally, plant prior to the 10th if moisture is available!
Our thanks to Chad Godsey, Oklahoma State University Cropping Systems Specialist, for providing this article on canola and the planting window this fall. This article was sent out as part of the Department of Plant and Soil Sciences Extension News - click here to find more articles from Extension News.
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