白菜属十字花科作物,生物期病虫害严重,药剂防治普遍,易造成产品的农药污染;白菜是速生蔬菜,菜农注重施用速效氮肥,易导致产品中硝酸盐含量超标;白菜食用普遍,限量物质超标产品严重影响人体健康。因此,研究并推广夏季白菜的无公害生产技术成为重要。一、播种时间南方地区可从3月份~10月份随时播种;北方地区可从5月上旬~8月上旬在露地可随时播种;一般利用春夏菜与秋茬菜之间的倒茬时间播种。 Cabbage is a cruciferous crops, pests and diseases are serious during the biological period, pesticide control universal, easy to cause pesticide pollution; cabbage is fast-growing vegetables, vegetable farmers focus on the application of quick-acting nitrogen fertilizer, easily lead to excessive nitrate content in products; Products seriously affect human health. Therefore, it is important to study and promote the pollution-free production of summer cabbage. First, the sowing time South from March to October sowing at any time; the northern region from early May to early August can be sown in the open at any time; the general use of spring and summer and fall stubble between the time of planting seeding.