For growers faced with uneven maturity within fields, it may not be possible to swath all the crop in the 50-60% seed colour change window. In situations where uneven maturity is the problem, the best approach is to swath when the most mature plants are close to 60% seed colour change, provided that the least mature plants are showing some seed colour change at the base of the main stem and that seeds in the upper pods (and branches) are dark green and firm (if maturity varies more than this consult the link regarding multi stage crops below). This will minimize yield loss from seed shrinkage and improve the odds that the seed will cure, although it will likely take longer and may require some more moist conditions. Swathing prior to 15 to 20% seed colour change will likely reduce some yield potential, and could contribute to green seed issues under hot and/or dry conditions.
More information is available on the “Canola Time of Swathing Guide” at the following link:
More information on harvesting a multi-stage crop is available at the following link: http://www.canola-council.org/uploads/Crop%20Production/Swathing%20and%20Harvesting%20Multiple%20Stage%20Crops%20MurDH%20-%20final%20draft%20(2).pdf