First, the choice of species. Choose cold-tolerant varieties that are resistant to twitching, such as: Italian stimulating lettuce for the whole year, crispy lettuce in Hong Kong glass, etc. Second, nurture strong seedlings. The lettuce seeds are small and the top soil ability is weak. Generally, seedlings are transplanted. The seedbed should be full of mature organic fertilizer, and the soil should be sifted. If conditions permit, soilless seedlings such as perlite and fine furnace can be used for seedling emergence. From the beginning of October to November, seedlings can be planted in greenhouses. The amount of mu for use is 20-25 grams. The seedbed needs about 10 square meters. Seeds should be soaked and germinated at 15-20°C before sowing. Seedlings were sowed before sowing, and finely ground 1-1.5 cm after spreading. When the seedlings grow to three true leaves, they can be planted at a spacing of 6 cm and 8 cm. The seedbed temperature is controlled at 18-20°C during the day and 12-14°C at night. The seedling age is generally 35-40 days. Third, rational planting. From November to January of the following year, when the seedlings had 5-6 true leaves, they colonized the winter in the greenhouse. Before planting, combined with site preparation, Mushi rotted 3,000 kg of organic fertilizer. The plant spacing is 25-30 cm and the row spacing is 20-25 cm. If the seedlings are harvested, they can be seeded at a spacing of 10 cm. Seedlings should be planted with soil as much as possible. The depth of colonization is appropriate to the root surface and the ground level, timely watering after planting, prompting rapid seedlings. Fourth, field management 1, temperature management. Cultivation of lettuce in winter greenhouses should pay attention to insulation. The daytime temperature is 18°C-20°C and nighttime is 13°C-15°C. Do not make the temperature too low, resulting in cold injury or frost damage. If the temperature is too high, it will cause the plants to be long and affect the quality. 2, fertilizer and water management. As raw vegetables are pollution-free vegetables, they can be used as raw vegetables. Therefore, it is not recommended to use manure and livestock manure in top dressing. Generally, urea is the main ingredient. Timely application of 3-4 times can be poured 0.3% urea after planting seedlings, 5 kg of urea per acre or so. In the future, it will be applied once every 10 days. It will be more watering if it encounters drought. After the closure of the line, it is generally no longer to fertilize the water, keep the surface slightly dry, watering for several days before harvest to facilitate storage and transportation. 3, pest control. Insect pests mainly include locusts and ground tigers. When locusts occur, they can be sprayed with 40% omethoate EC 1000 times or 10% imidacloprid WP 4000 times. If there is a hazard to the ground tiger, 90% trichlorfon can be sprayed on the ground to control 800 times. Diseases mainly include downy mildew, soft rot, and sclerotia. Downy mildew can be sprayed with 75% chlorothalonil wettable powder 500 times; soft rot can be sprayed with 72% agricultural streptomycin sulfate powder 4000 times in time; Sclerotinia can be used 80% carbendazim ultrafine powder 600 times liquid Spray, spray once every 7-10 days, even spray 2-3 times. V. Harvesting. The harvesting of lettuce should not be delayed as soon as possible to ensure its fresh quality. When the plants have 15-25 leaves and the weight is 100-300 g, they are harvested in time. Mu harvest about 1500 kilograms.