定值期的确定早春保护地蔬菜栽培要保证春天的淡季蔬菜供应，一般在2月中下旬定植，如黄瓜、番茄和辣椒等；秋延迟栽培的黄瓜、番茄多在9月上中旬定植；而越冬黄瓜、西葫芦等蔬菜，为供应元巳、春节币场，一般在L一年的10月中下旬定植。适宜苗期的确定各种蔬菜生长发育特点及对 Determination of the fixed-term period In early spring vegetable cultivation in protected areas to ensure that the supply of vegetables in the spring off-season, usually in late February planting, such as cucumber, tomato and pepper; late autumn cultivation of cucumber, tomato and more in mid-September planting; Overwintering cucumbers, zucchini and other vegetables, for the supply of Yuan Pat, Lunar New Year currency market, generally in L a year in late October planting. Suitable for seedling to determine the characteristics of various vegetables and growth and development