Winter planting techniques of lettuce

Variety selection should select cold-resistant strong mid-late maturity heading lettuce varieties for cultivation.

Cultivation dates Sunlight greenhouse cultivation can be planted from mid-late November to late January of the following year, and harvested from mid-January to early March.

Seedling selection fertile sandy loam, fine after making flat bed. Then every 10 square meters, 100 kg of sieved high-quality manure and 0.5 kg of potassium dihydrogen phosphate are applied, mixed well, watered after leveling the ridge surface, and seeds are scattered after water infiltration. Dry seeds are generally used for sowing, and seeds can also be soaked and germinated. When sowing dry seeds, first dress seeds with 75% chlorothalonil wettable powder equivalent to 0.3% of seed weight, but it is not advisable to leave them for too long. Soaking germination, should be soaked in warm water at 20℃ for 6~7 hours, take out after wrapping with cloth bag, placed at 20℃ germination, washing with water once a day, 2~3 days after the full bud. Sowing is carried out in the windless sunny morning, and 3 to 5 grams of seeds are sown per square meter of seedbed. After sowing, cover with a layer of fine soil 3~5 mm thick.

Before soil preparation, fertilization and planting, 5000 kg decomposed organic fertilizer and 30~40 kg compound fertilizer shall be applied per mu. After deep ploughing, it can be made into flat ridge, and plastic film covered can be made into small high ridge.

Planting sunlight greenhouse cultivation row spacing of 40 cm, plant spacing of 30 cm, watering before the seedlings cut Tuofu, more with some soil. Furrowing or digging holes for planting, sealing furrows and leveling ridges, watering enough planting water.

After colonization, the temperature was kept at 20℃~24℃ during the day and above 10℃ at night. Cultivate and loosen soil for 1~2 times during the period of slow seedling. After the seedling is slowed down, the temperature should be lowered appropriately, and the temperature should be 15℃~20℃ in the daytime. The seedling is watered 7~10 days after the seedling is slowed down, and the chemical fertilizer is lightly applied, and about 10 kg is applied per mu. Then cultivate again and squat properly. After about 15 days, when the lotus leaves have grown and the heart leaves begin to cover the heart, apply compound fertilizer or ammonium nitrate 15~20 kg, and then apply fertilizer once during the ball setting period. Winter watering times should not be too much, in order to prevent lowering the ground temperature or humidity is too large. When entering the ball stage, the water supply should be uniform, and it should not be dry and wet, so as not to crack the ball or make the ball leaf open and grow. Stop watering 3 - 5 days before harvest.