Selection of lettuce varieties:
Lettuce varieties should select low temperature tolerance, low light intensity, early maturity, high yield and good disease resistance in deep winter stubble. At present, the more suitable varieties are Italian hemispherical lettuce, American saffron leaf lettuce (8101) and selenium Tianyang 44 lettuce.
Lettuce cultivated in deep winter in the greenhouse is usually sown from late October to early November, planted from late November to early December, and harvested from early January to around the Spring Festival.
Processing methods of lettuce seeds:
Soil disinfection was carried out by mixing seeds with 75% chlorothalonil powder or 50% carbendazim wettable powder, or spraying seed beds with 500-600 times liquid before sowing. Attention should be paid to seeds immediately after seed dressing.
Seedbed soil selection: the seedbed soil should be selected with good soil fertility and good sandy loam.
Seed of lettuce sowing method: usually sowing, when sowing, mixed with fine sand to sow evenly, after sowing, covered with 0.3-0.5 cm wet soil, and covered with plastic film moisturizing. The planting amount per mu is 30-50 g.
Management methods of raw vegetable seedlings:
The suitable temperature of lettuce in germination period is 15-20℃. When the seedlings begin to unearthed, they should uncover the plastic mulch in time to prevent the growth.
The temperature of seedbed is 18℃-20℃ and 12℃-14℃ at night.
Attention should be paid to ventilation and ventilation.
Water is not watered at seedling stage. When the seedlings wilt, some water can be sprayed, 75% chlorothalonil 600 times liquid can be sprayed once or twice, combined with spraying double-effect micro-fertilizer to achieve the purpose of disease prevention and cultivation of strong seedlings.
Field management of lettuce:
Temperature management: After slow seedling, the temperature should be maintained at 18℃-22℃. During the heading stage, the suitable temperature should be 20℃-22℃ in the daytime and 12℃-15℃ in the night.
Fertilizer and water management: after planting and watering seedlings, it is advisable to pour water 3-4 times later.