In Tian Jia's Song of the Four Seasons, four kinds of farming, including sericulture, transplanting, farming and rice farming, are described. Silkworm rearing is generally carried out in spring and summer. At this time, the mulberry tree is in the vigorous growth period, and the encroachment is guaranteed. Transplanting is generally carried out in summer, especially in April-May, when the temperature of paddy field is very suitable for seedling growth. Farming is generally carried out in spring and autumn, with one tillage before transplanting and two tillage after autumn harvest.
China folk customs take January, February and March of the lunar calendar as spring; April, May and June are summer; July, August and September are autumn; October, November and December are winter.