No Killing Frost – Yet

The first fall frost (killing frost) has not happened yet anywhere in western Canada and to date no frost appears to be in the forecast. So far this is giving the later canola a chance to fill and ripen naturally. Producers for the most part appear to be able to wait for 60% seed colour change before swathing. However if a killing frost is predicted, keep in mind that in order for canola to be protected it should be cut early enough to allow sufficient dry down before the frost (typically at least 3 days ahead). Past research by the Canola Council has shown that swathing earlier (30 to 40% seed colour change) resulted in approximately a 7% yield loss compared to swathing at 50 to 60% seed colour change. If a killing frost is predicted (in the neighborhood of -2⁰C or lower for a significant period of time), it is probably a better strategy to cut early and risk suffering that yield penalty rather than suffer significant frost damage (which can impact both yield and quality). If the crop is exhibiting only 20 to 30% seed colour change, check to see that the seeds on the side branches are firm rather than mushy. This will minimize yield loss from seed shrinkage and improve the odds that the seed will cure in the swath, although it will likely take longer and may require some more moist conditions. Swathing prior to 15 to 20% seed colour change should only be considered if the frost risk is severe, because swathing that early can significantly reduce yield potential and contribute to green seed issues if the frost does not materialize.