What month was winter buckwheat planted?

In China, buckwheat is sown all year round: spring sowing, summer sowing, autumn sowing and winter sowing, also known as spring buckwheat, summer buckwheat, autumn buckwheat and winter buckwheat. Spring sowing is common in dry farming areas in northern China, and once a year in alpine mountainous areas; Sowing in summer in winter wheat area of the Yellow River Basin; South of the Yangtze River and south-central coastal areas are often sown in autumn; In subtropical areas, seeds are often sown in winter; Sow in spring or autumn in southwest plateau. The specific suitable sowing date in each producing area should be based on the variety maturity (growth period), the local frost-free period and the effective accumulated temperature number of > 10℃, and the basic principle is to avoid the local high temperature (> 26℃) and ensure the maturity before frost in the full flowering period of buckwheat.