Optimal swath timing for canola yield and quality is when at least 60% of seeds on the main stem are showing some colour change. Here’s how to determine seed-colour change.
Step 1. Start inspecting your canola field approximately 10 days after flowering ends. The end of flowering is reached when only 10% of plants have any flowers remaining.
Step 2. Take time to assess a field. Sample at least 5 plants in several locations throughout the field to make an accurate assessment of the overall maturity of the crop. Stand on the road or in the back of your truck box to help identify the ripest and least mature areas of the field (e.g. low lying vs. higher elevated areas of the field,) and ensure these areas are included in your sampling.
Step 3. Use the illustration to assist in determining seed colour percentage on the main stem. Include seeds with small patches of colour (spotting). Also look for firm seeds in the top pods that should roll between the thumb and the forefinger without being easily crushed. Note that pod colour is not a good indicator of seed colour change. Pods have to be opened.
Step 4. Low plant populations can lead to plants with numerous branches (see picture top right). For these plants assess not only the main stem, but side branches as well to ensure seeds that are still green are firm with no translucency.
Step 5. Once all areas are sampled, average out the percent seed colour change for that particular field. Also note the range in maturity observed among sampling locations.
Step 6. Continue inspections every two to three days until ready to swath.
Source: Canola Watch