莴笋以肉质嫩茎供食用 ,既可生食 ,又可熟食 ,还可加工出口。它是供应春淡季市场的主要蔬菜之一。近年来 ,我县菜农利用塑料大棚覆盖栽培 ,可将上市期提早到 2月中旬左右 ,较露地越冬春莴笋提前 4 0～ 50天上市 ,平均单产 1 50 0千克 ,高产可达 2 0 0 0千克 ,经济效益十分可观 Lettuce tender stems for meat consumption, both raw food, but also cooked food, but also export processing. It is one of the main vegetables that supply the spring and autumn markets. In recent years, our county vegetable farmers covered with plastic greenhouses, the market can be early to about mid-February, compared with open and wintering spring lettuce 40 to 50 days in advance market, with an average yield of 1,50 0 kg, high yield up to 2000 Kg, the economic benefits are considerable