Winter wheat

Winter wheat (usually Triticum aestivum) are strains of wheat that are planted in the autumn to germinate and develop into young plants that remain in the vegetative phase during the winter and resume growth in early spring. Classification into spring or winter wheat is common and traditionally refers to the season during which the crop is grown in the Northern Hemisphere. For winter wheat, the physiological stage of heading is delayed until the plant experiences vernalization, a period of 30 to 60 days of cold winter temperatures (0° to 5 °C).

Winter wheat is usually planted from September to November in the Northern Hemisphere and harvested in the summer or early autumn of the next year. In some places (e.g. Chile), winter wheat even celebrates a "birthday", meaning it is harvested more than a year after it was planted. Winter wheat usually provides higher yields compared to spring wheat.

So-called "facultative" wheat varieties need shorter periods of vernalization time (15 – 30 days) and temperatures of 3° to 15 °C. In many areas facultative varieties can be grown either as winter or as a spring, depending on time of sowing.