Winter canola varieties planted in the fall have always shown a potential for improved yield over spring-planted varieties. This is true primarily because winter canola has more time to develop in the field, and it flowers under more ideal weather conditions. The most significant problem with winter canola is its inability to survive winter conditions.
In regions where temperatures over 90° F are common when spring canola flowers, winter canola may be more suitable if it can survive the winter in that climate. Plant breeders have not yet found a winter canola variety that can consistently survive the winters in North Dakota, northern Minnesota and much of Montana.
Both public and private breeding companies have developed and selected varieties with superior winterhardiness for many years. Winter tolerance is complicated, influenced by many cultural and environmental conditions. No varieties are available for the north-central region of the country, including Minnesota, North Dakota, Wisconsin and much of Montana.
CROPLAN GENETICS® seed includes one winter canola hybrid and two open-pollinated varieties (including one that is Roundup Ready®) for the fall planting season that will fit in most potential winter canola growing regions in the United States.
The fall planting date is the most critical cultural practice to establish a canola crop before a killing frost. Planting too early can result in large plants with crowns that start to elongate and become exposed to cold winter weather. These plants have a higher risk of dying due to freezing or wind desiccation. Planting too late will prevent the plant from building up the food reserves necessary to regenerate in the spring.
It is estimated that winter canola should be planted about six weeks prior to the date when there is a 50 percent chance of a killing frost (under 25° F).