Proper Stage to Swath Canola

The color of canola seed is more important than the overall color of the field in determining the stage of maturity. The best time to swath for optimum seed yield and quality is when all the seeds contain about 30 to 35 percent moisture. The color of the seeds is a good indicator of seed moisture contents. Seeds in all pods on a plant complete filling (physiological maturity) at about 40 percent moisture and then slowly turn from green to light yellow, or reddish brown to brown, depending on the variety. Once filled, the seeds rapidly lose moisture at about 2 to 3 percent or more per day, depending on the weather.

Examine only those pods on the main stem. Seeds in pods on the bottom third of the main stem were formed earlier and will turn color much sooner than seeds in the pods of the top third of the plant. When the overall moisture content of seed from the total plant averages 30 to 35 percent, about 30 to 40 percent of the seeds in pods on the main stem only will have changed color or have started to change color. Seeds with only small patches of color should be counted as color changed.

Most of the seeds will be firm, and roll, as opposed to break, when pressed between the forefinger and thumb.

Swathing late, when seed moisture content is much lower (around 80 percent seed color change), will result in fluffy windrows susceptible to blowing and increased shattering. To reduce shattering losses, over-ripe fields should be swathed when humidity is high, such as after a rain, after a heavy dew, or at night.

During hot windy weather, canola can change from too green to too ripe in two to three days. As maturity approaches monitor fields carefully. Timely swathing will prevent huge shattering losses.