早春大棚黄瓜经常出现苦味，严重时无法食用，直接影响了其商品价值，导致栽培效益锐减。发生原因：门）种植过早，温度低北方地区早春大棚黄瓜（冬春茬黄瓜）种植期一般在3月下旬，有的农户为了卖个好价钱，往往在低温逆境条件下论早栽培（如3月20日左右）。此时棚内夜间温度? Early spring greenhouses cucumbers often appear bitter, can not eat in serious cases, a direct impact on the value of their products, resulting in sharp reduction in cultivation efficiency. Occurrence reason: The door is planted prematurely, the temperature is low Early spring greenhouses cucumbers (winter and spring cucumbers) in the north are generally planted in late March. Some farmers tend to sell early at low temperature under adverse conditions March 20 or so). At this time shed night temperature?