How to assess seed-colour change

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 (See page 1 here) 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.

This is what seeds at the top, middle and bottom of the main stem will look like at 60% seed colour change.

Step 4. Always inspect seeds in side-branches as well, particularly in fields with low plant populations that have a large amount of branching. Prior to swathing, these seeds should be at least firm to roll without any translucency, but they may still be green.

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.

Dig deeper: