The optimal swath timing for canola yield and quality is when 60% of seeds on the main stem are showing some colour change. Seed colour change (SCC) is considered any amount of yellow or brown on the seed.
“To determine when to swath a field, growers need to walk the field and crack pods. Pod colour change is not an accurate indicator of seed colour change,” says Angela Brackenreed, agronomy specialist for the Canola Council of Canada. “In some cases, pods can appear ripe on the outside but the seeds are still green. Or pods can be green while seeds inside are brown.”
To assess SCC, start in an area of the field that best represents the stand, stage and yield potential of the crop. Pull a plant and isolate the main raceme, which is typically the longest branch with the most pods — representing the greatest percentage of yield. Take pods from the bottom, middle and top of the main raceme. “For 60% seed colour change, seeds from pods at bottom third of the main raceme will be totally brown to purplish brown, seeds from the middle third will be starting to turn, and seed from the top are green but firm and will roll between your thumb and forefinger without mushing,” Brackenreed says.
Check five plants in this area, then repeat in another couple of places in the field. “Don’t make the decision based on one plant,” she says.