Old leek is a kind of Yezi opera that spreads in Qidong, Jiangsu and other places. It is also a two-part allegorical saying, which can be regarded as a metaphor. Leek is a perennial root vegetable of Liliaceae, which has strong adaptability, cold resistance and heat resistance and is cultivated all over China. Many areas in the south can be produced all year round. In the north, although the aboveground part dies in winter, the underground part goes into dormancy, and the topsoil germinates and grows after thawing in spring. Leek is cool, cold-resistant and heat-resistant. The optimum temperature for seed germination is above 65438 02℃, and the growth temperature is between 65438 05℃ and 25℃. The underground part can withstand lower temperatures.