To plant autumn lettuce well, choosing the right technical measures is the king.

Autumn lettuce is prone to bolting and cracking in the growth process, which seriously affects the quality and yield of the product. We have taken the following technical measures in practice and achieved good results.

First, to select improved varieties and sow autumn lettuce at the right time, we should choose mid-late maturing varieties with high temperature resistance, not easy bolting, high quality and high yield, such as Sichuan Erbaipi, Shanghai pointed leaf lettuce and so on. Sowing seeds at the beginning of August, low temperature germination treatment must be carried out before sowing, that is, after the seeds are packed in gauze bags and soaked in cold water for 5 hours, hang the gauze bags 30 centimeters above the water surface in the well or place them in the refrigerator cold room to accelerate germination, wash them once or twice a day, and sow 60% or 70% of the seeds in about 3'5 days.

Second, sunshade seedlings, reasonable close planting in early August, the temperature is higher, seedlings must be shaded, the method is: after sowing with grass curtain, sunshade net flat on the bed, after emergence, the curtain, net height of about 1 meter, in order to ventilation. The seedlings were covered throughout the day in the early stage, covered at 9 am and uncovered at 4 pm in the middle sunny day, and gradually covered and uncovered early in the later stage to facilitate seedling refinement. The seedlings were transplanted within 25 to 30 days after emergence. Due to the growth of autumn lettuce under hot conditions, the plant type is generally small, so the planting density can be increased to 5500-6000 plants per mu. After planting, it is best to cover it with sunshade net and so on, and then gradually remove the cover in about 10 days.

Third, apply enough base fertilizer and choose the field with fertile soil to plant autumn lettuce in time. Before planting, deep ploughing and sun-drying, 2500-3000 kg of human and animal fertilizer and 35-40 kg of cake fertilizer were applied per mu as base fertilizer. One week after planting, combined with ploughing and weeding, 150 kg of dilute dung water plus 5 kg of urea per mu and 0.2% potassium dihydrogen phosphate solution were applied. Before closing the row of autumn lettuce, apply dilute manure water and phosphate fertilizer for 2 or 3 times according to the condition of the seedling.

Fourth, spraying hormones to control diseases and insect pests in order to prevent bolting of autumn lettuce, spray 0.1% Daizhuangsu solution at the end of the rosette stage and spray it again every 7 to 10 days. Pick the heart when the buds are visible to the naked eye. There are more Rain Water in autumn, and lettuce is prone to downy mildew. 90% ethyl phosphate aluminum 500x or 75% chlorothalonil wettable powder can be sprayed at the initial stage of the disease, once every other week, for a total of 3 times. The main pests of autumn lettuce are aphids and red spiders. Aphids can be controlled with 50% Baofa No. 1 EC 1500 ~ 2000 times, and red spiders can be controlled with 1000 times of dicofol EC.