Lettuce is not strict with the requirements of the former, and can be used in conjunction with other leafy vegetables. Rotation can also reduce disease, increase yield and improve quality. It is best to use melons, solanes, beans and onions and garlics before cooking. Although the lettuce cultivation time is long, the planting time is small when planting, and the time required for planting to harvest is shorter, and it can be cross-planted with cucumber, bean, tomato and the like.

According to the characteristics of lettuce, cold and high temperature, it can be cultivated in spring and autumn. In Shandong and North China, seedlings are planted in spring and February, and harvested from May to June. Autumn is in late July to 8 Seedlings are planted in the second half of the month and harvested from October to November. In addition to spring and autumn cultivation, lettuce can also be grown in the summer under shading conditions, such as using shade nets or enamel foil shades or intercropping with sorghum vegetable crops. In recent years, with the development of vegetable greenhouses and the improvement of economic benefits of planting, it is possible to carry out cultivation in deep winter and early spring in winter-heated greenhouses with good results. Due to the low ground temperature during this period, the required growth period and harvest period are longer. The seedling period takes 30-40 days, and it takes about 60 days from planting to harvesting. It can be harvested according to market needs. Therefore, the planting time is more flexible. If it is listed during the New Year's Day to the Spring Festival, it can be planted in the middle and late October. In early spring, it can be planted in December or early in mid-November. Due to the combination of open field cultivation and protected field cultivation, annual supply can be achieved. In order to make full use of the land and sunlight and improve the economic benefits of lettuce, lettuce can adopt the following three-dimensional planting mode:

(1) Three kinds of crops in the greenhouse, such as spring pepper, lettuce and bean, are used for large and small intercropping. Small 畦 80 cm, planted lettuce. It is 120 cm wide and can be planted with 3 rows of peppers. Lettuce can be planted with round leaf varieties in mid-January. The seedling age is about 40 days, and colonization is carried out in late February. Each row is planted in 2 rows, with a plant spacing of about 30 cm, and about 1800 plants per 667 square meters. After the planting, cover the small arch shed. The market will be harvested in April and mid-April. Pepper can be planted in the middle and late December of the previous year. The seedling age is about 90 to 100 days. In the middle of March, the planting is carried out. The hole distance is about 30 centimeters. Two plants are planted at each hole, which is equivalent to 6,000 plants per 667 square meters. After the peppers are planted, the small arch shed over the lettuce is removed and covered onto the pepper. After the lettuce is harvested in the middle and the middle of April, two rows of kidney beans can be sown in the stalks of the original lettuce, with a hole distance of about 20 cm and 2 to 3 plants per hole. After the bean is set up, the pepper can be shaded.

(2) Cucumber, chayote, and lettuce can be used to interplant cucumbers with Jinchun No. 2. In mid-February, the seedlings can be planted in the greenhouse first, and then planted in the greenhouse in mid-March. The row spacing is about 80 cm, the plant spacing is 20 cm, and about 4,000 plants are planted per 667 square meters. Harvesting began in mid-April and was pulled to the end of June to end production. The chayote can be bagged and germinated from November of the previous year, and then the nutrient soil seedlings are placed in a bottomless plastic bag with a diameter of 20 cm, and one melon seed is contained in each bag. In the middle of April, in the front of the shed, along the front shed and the front of the cucumber row, a pit of about 1 meter in length, width and depth is about every 4 meters, and 250 kilograms of decomposed organic are applied in each pit. 10 kg of fertilizer, diammonium phosphate and potassium sulfate, filled with water, and 1 pitted with a chayote seedling.