The ideal swath timing for top yield is when average seed colour change across the field is at least 60% on the main stem. But canola growers may want to reassess that approach based on the following considerations.
Calendar date. By mid September, the frost risk is higher – as is the risk for frost many nights in a row. Because heavy frost can lead to pod drop and pod splitting, swathing before or after a frost can provide some protection. It isn’t perfect because split pods can still occur in a swath. Farmers may want to start swathing the most mature fields just in case heavy frost strikes. Note that the ideal response to frost is to assess the level of damage AFTER a frost occurs and then, if frost is heavy and pod-drop is a risk, swath.
Heavy frost is in the forecast. Canola needs three good curing days between swathing and frost before it dries down to a safe levels to prevent frost from locking in high green and to reduce the risk of pod splitting and pod drop. “Good curing days” have to be warm and dry. This time of year, good curing days can be hard to come by…so “three days” might actually be seven or 10 to cure down to the point where frost has minimal risk. But swathing ahead of the frost might be the best decision if the goal is to get harvest progressing, because swathed canola will cure faster than standing canola.