How to Grow Lettuce in Winter? Detailed Methods and Key Technical Points
How do you grow lettuce for the winter market? Is there anyone who can guide me on winter lettuce cultivation? You can refer to the following growing methods for cultivation (for reference). 1. Lettuce variety selection: Choose cold-tolerant, bolting-resistant varieties, such as Italian year-round bolting-resistant lettuce, Hong Kong glass crisp lettuce, etc....
How do you grow lettuce for the winter market? Is there anyone who can guide me?For winter lettuce cultivation, you can refer to the following growing methods for cultivation (for reference).
1. Lettuce variety selection:
Choose cold-tolerant, bolting-resistant varieties, such as Italian year-round bolting-resistant lettuce, Hong Kong glass crisp lettuce, etc.
2. Lettuce seedling cultivation:
Lettuce seeds are small and have weak soil-piercing ability, so seedling raising and transplanting are generally used. The seedbed should be given sufficient decomposed organic fertilizer, leveled and raked fine, and the covering soil should be sieved. If conditions permit, soilless seedling raising with light substrates such as perlite and fine furnace cinders is even more conducive to emergence.
From early October to November, sowing and seedling raising can be carried out in greenhouses, with 20-25 grams of seed per mu, requiring about 10 square meters of seedbed. Before sowing, the seeds should be soaked and pregerminated at 15-20°C. The seedbed should be irrigated before sowing, and after broadcast sowing, cover with fine soil 1-1.5 cm. When the seedlings grow to 3 true leaves, they can be separated at a plant spacing of 6 cm × 8 cm. The seedbed temperature should be controlled at 18-20°C during the day and 12-14°C at night. The seedling age is generally 35-40 days.
3. Lettuce transplanting and field planting:
From November to January of the following year, when the seedlings have 5-6 true leaves, plant them in greenhouses to overwinter. Before planting, in combination with land preparation, apply 3000 kg of decomposed organic fertilizer per mu, deep plow, then level and make flat beds. At planting, the plant spacing is 25-30 cm and the row spacing is 20-25 cm. If harvesting young seedlings, just set the plants at a row and plant spacing of 10 cm. Try to transplant seedlings with soil. The planting depth should be such that the root-soil surface is level with the ground surface. Water promptly after planting to promote rapid recovery.
4. Routine field management methods for lettuce
1. Temperature management:
Winter greenhouse lettuce cultivation should focus on heat preservation. Keep the daytime temperature at 18°C-20°C and the nighttime temperature at 13°C-15°C. Do not let the temperature get too low, causing chilling injury or freezing injury; if the temperature is too high, it will cause excessive vegetative growth and affect quality.
2. Fertilizer and water management:
Since lettuce is a pollution-free vegetable and can be eaten raw, it is not recommended to use human and livestock manure for topdressing; generally, urea is mainly used. Apply topdressing 3-4 times at the right time. After planting and recovery, water with 0.3% urea solution, using about 5 kg of urea per mu. After that, apply once every 10 days, and water more in case of drought. After the rows close, generally no more fertilizer or water is applied, keeping the bed surface slightly dry. Stop watering several days before harvest to facilitate postharvest storage and transportation.
3. Pest and disease control:
The main insect pests include aphids, cutworms, etc. When aphids occur, promptly spray 40% omethoate emulsifiable concentrate 1000-fold solution or 10% imidacloprid wettable powder 4000-fold solution for control. If cutworms are causing damage, spray the ground with 90% trichlorfon 800-fold solution for control.
The main diseases include downy mildew, soft rot, sclerotinia rot, etc. For downy mildew, spray 75% chlorothalonil wettable powder 500-fold solution; for soft rot, promptly spray 72% agricultural streptomycin sulfate soluble powder 4000-fold solution; for sclerotinia rot, spray 80% carbendazim ultrafine powder 600-fold solution, once every 7-10 days, for 2-3 consecutive sprays.
5. Lettuce harvest:
Lettuce should be harvested early rather than late to ensure its fresh and tender quality. When the plants have 15-25 leaves and a plant weight of 100-300 grams, harvest promptly. The yield per mu is about 1500 kg.
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