我省位于北纬31°25′——36°20′,属华北蔬菜双主作区,蔬菜生产为两淡两旺类型。冬季寒冷干燥,除耐寒性强的绿叶菜类、葱蒜类蔬菜能露地越冬外,绝大部分蔬菜冬季难以露地生产。夏季炎热多雨,蔬菜生长不良,上市量少,品种单调,形成8、9月 My province is located at latitude 31 ° 25 ’- 36 ° 20’, is a double crop of vegetables in North China, vegetable production is two kinds of light and two types. Winter cold and dry, in addition to strong cold green leafy vegetables, onion and garlic vegetables can be exposed to winter, the vast majority of winter vegetables difficult to open-air production. Summer hot and rainy, poor vegetable growth, less market, monotonous species, the formation of August and September