Key points of lettuce cultivation in solar greenhouse

In the selection of varieties in deep winter, lettuce varieties with tolerance to low temperature, weak light, early maturity, high yield and good disease resistance should be selected. at present, the more suitable varieties are 14624 heading lettuce, mosaic lettuce and glass lettuce.

Lettuce is cultivated in solar greenhouse in deep winter, generally sowing and raising seedlings from late October to early November, planting from late November to early December, and harvesting from early January to Spring Festival. Seed treatment: before sowing, sow seeds with 75% chlorothalonil powder or 50% carbendazim wettable powder, or spray the seed bed with 500% 600 times liquid to disinfect the soil. Note that the seeds should be sown immediately after seed mixing, and do not put them overnight. Sowing: the seedbed soil should choose sandy loam with good water and fertilizer conservation and fertile. Bed and soil preparation: 10 square meters of seedling bed with 10 kg of rotten organic fertilizer, 0.3 kg of ammonium sulfate, 0.5 kg of calcium superphosphate, 0.2 kg of potassium chloride, fully mixed and evenly paved fine, poured enough bottom water, sowed after water infiltration. Sowing method: generally use sowing, sowing can be mixed with fine sand to sow evenly, cover 0.3 cm 0.5 cm fluvo-aquic soil after sowing, and cover with plastic film to moisturize. The sowing rate is 30,50g per mu. Seedbed management: the optimum temperature of lettuce at germination stage was 15 ℃ ~ 20 ℃. When the seedlings begin to be unearthed, the plastic film on the border should be opened in time to prevent overgrowth. The suitable temperature of seedling bed is 18 ℃ ~ 20 ℃ in daytime and 12 ℃ ~ 14 ℃ at night. Pay attention to ventilation, shading is needed in case of strong light exposure. To ensure the normal growth of seedlings. When the seedlings grow to 2-3 true leaves, the seedlings are divided according to the row spacing of 6-8 cm, and when they grow to 4-5 true leaves, they can be planted. There is no shortage of water in the seedling stage. When the seedlings wilt, you can sprinkle some water, spray 75% chlorothalonil 600 times twice, combined with spraying double-effect micro-fertilizer to achieve the purpose of disease prevention and cultivation of strong seedlings.

The soil should be ploughed carefully when preparing for soil preparation before planting. Apply sufficient basic fertilizer before planting, apply rotten farm manure 3000mu to 3500kg per mu, turn deeply and water the bottom water after sprinkling, make the bed after it is dry, and it is better to cultivate with high border and plastic film mulching in late winter.

In the colonization method, the seedling bed was irrigated one day before planting to make the seedling moist, and the seedlings were raised with as much soil as possible the next day to reduce root damage. When planting, the ditch was first opened on the border surface, and then irrigated according to 25 kg of nitrogen and phosphorus compound fertilizer per mu. After water infiltration, the seedlings were arranged to cultivate the soil and seal the ditch according to the plant distance of 24 cm. The border surface was raked flat, covered with plastic film, and the seedlings were introduced into plastic film.

Field management temperature management: the temperature was kept at 18 ℃ ~ 22 ℃ after slow seedling, 20 ℃ ~ 22 ℃ during the day and 12 ℃ ~ 15 ℃ at night during the heading period. Fertilizer and water management: slow seedling water after planting, and then watering for 3 times and 4 times is suitable.