How to grow autumn lettuce? Choosing the right technical measures is key

During growth, autumn lettuce is prone to bolting, cracking and other problems, which seriously affect the quality and yield of the product. In practice, we adopted the following technical measures and achieved very good results.

1. Select good varieties,Sow at the right time. To grow autumn lettuce, choose mid-to-late maturing varieties that tolerate high temperatures, resist bolting, and offer good quality and high yield, such as Sichuan Erbaipi and Shanghai pointed-leaf lettuce.8Sow at the beginning of the month. Before sowing, low-temperature germination treatment is required: put the seeds in a gauze bag and soak them in cold water for5～6hours, then hang the gauze bag in a well30cm above the water surface, or place it in the refrigerator crisper to germinate. Rinse it every day1～2times; after about3～5days,60%～70%when the seeds show white sprouts, they can be sown.

2. Shade for seedling raising,reasonable close planting8At the beginning of the month, the temperature is relatively high, so shading is essential when raising seedlings. The method is: after sowing, lay straw curtains or shade nets flat on the bed surface; after emergence, raise the curtains and nets to about1m to allow ventilation. In the early stage of seedling raising, cover all day; in the middle stage, cover at9a.m. on sunny days and uncover at4p.m.; in the later stage, gradually cover later and uncover earlier to help harden the seedlings. After emergence,25～30days later, thin and transplant the seedlings. Because autumn lettuce grows under hot conditions, the plant type is generally not large, so the planting density per mu can be increased to5500～6000plants. After transplanting, it is best to cover with shade nets and other materials on a raised frame,10and then gradually remove the covering after about

days.3. Apply sufficient base fertilizer,2500～3000and topdress in time. Choose fertile field soil to plant autumn lettuce. Before transplanting, deep plow and sun the soil, and apply35～40kg of human and livestock manure and150kg of cake fertilizer per mu as base fertilizer. One week after transplanting, combined with intertillage and weeding, apply5kg of diluted manure water plus0.2%kg of urea and a2～3% potassium dihydrogen phosphate solution per mu. Before autumn lettuce closes its rows, topdress with diluted manure water plus phosphate fertilizer

times depending on seedling condition.4. Spray hormones,0.1%prevent and control pests and diseases. To prevent autumn lettuce from bolting, spray a7～10% chlormequat chloride solution at the end of the rosette stage, and spray again after90%days. Pinch the growing point when small flower buds can be seen with the naked eye. In autumn there is more rain, and lettuce is prone to downy mildew. At the early stage of the disease, spray500% phosethyl Al75%times dilution or600% chlorothalonil wettable powder3～4times dilution, once every week, for a total of50%times. The main pests of autumn lettuce are aphids and red spiders. For aphids, use1Baofa1500～2000No. emulsifiable concentrate20%times dilution; for red spiders, use1000dicofol emulsifiable concentrate