The key to high yield of lettuce is lettuce
Because of the different cultivation seasons, there are two forms of open field nursery and protected land nursery. Seedlings can be sown on the field in the production field, and nutritious soil blocks, paper bags or nutritious pots can also be used. The nursery bed soil is 50% decomposed horse manure and 50% garden soil. At the same time, 20 grams of urea and 250 grams of superphosphate are added per cubic meter of bed soil. After mixing and sieving, the bed is laid flat on the seedbed and is 5 to 10 cm thick. .
Second, choose a good species
Leaf-type lettuces have cabbage lettuce and leaf lettuce, as well as half-leafed lettuce. Production of many use of cabbage lettuce, such as the United States, the emperor and the Great Lakes 659, Japan's Olympia, etc., more heat-resistant, shorter growth period.
Third, disinfection and germination
Lettuce seeds are small and germinate quickly, and dry seeds are generally used more often. Seeds are generally only sterilized by air drying. If soaking germination, then first soaked in cold water for 5 to 6 hours, then placed in the conditions of 16 °C ~ 18 °C see light germination, after 2 to 3 days to bud.
Fourth, appropriate sowing
Lettuce can be produced for many years, so it is also possible to grow more seedlings. The lettuce harvested from April to May can be planted in spring from March to March. For lettuce harvested from May to June, heat-resistant, disease-resistant and late-stemming varieties should be selected, and sown in April. The lettuce harvested from September to October is generally sown in June to July. The lettuce harvested in winter is generally sown in October. It can be produced in solar greenhouses in the winter and colonized after harvesting. In the sowing nursery bed, you can sow at any time, sowing a plant every month, planting a plant, harvesting a plant, so that the planting, planting, harvesting.
V. Strong seedling standards
Generally nursed in nursery for 30 to 50 days, with 6 to 7 leaves, more fibrous roots, dark green stems, thick, large and wide leaves, plant height about 15 cm, plant pest free and mechanical damage. The seedlings for direct seeding in the open season are suitable for 30 days, and 4 to 6 leaves for seedlings.
Six, fine sowing
Before sowing, the footbed water shall be poured on the seedbed, and 0.5 cm thick fine soil shall be sprinkled after the water is soaked. Generally, the seeding rate per square meter is 5 to 10 grams. After sowing, the fine fluvo-aquic soil is 0.5 to 0.8 cm thick, and the soil temperature is maintained at 15 to 18 DEG C. The cover plastic film or straw curtain is moisturized. Generally, it can be excavated in 3 to 5 days. . If the seedlings are planted in open field, about 10 days after emergence (1 leaf stage), the seedlings can be carried out so as not to affect the growth of seedlings.
Seven, seedling management
In the 2 to 3 leaf stage of lettuce, it can be transplanted. The seedling spacing should be 6 to 8 cm. It is advisable to grow 1 seedling for each nutrient crop or paper bag. Before the transplant, adequate water should be poured. After the planting, the depth of planting should be maintained at the original level. Transplanting seedlings, moisture preservation, the temperature of about 20 °C is appropriate. After easing the seedlings, cultivating roots should be done frequently to prevent the adverse effects of excessive humidity and high temperature and rain in the summer. During the seedling stage, watering should be done with a small amount of water to keep the beds moist. In summer and autumn, seedlings should be protected from rainstorm and high temperature and drought. Rainproof seedlings and shade nets can be used to cover seedlings. The shade net is usually covered in the morning from 8 am to 4 pm on sunny days and it can be uncovered at night or on cloudy days. Dry weather should be diligently watered in the morning and evening. It can be top-dressed with watering, and it is usually chased 1 to 2 times with dilute manure. It can also be top-dressed with 0.3% potassium dihydrogen phosphate. About 30 days after sowing, the requirements for low temperature and short days should be met, so that early jerking can be prevented.
VIII. Precautions
It is necessary to prevent rat damage during the entire lettuce breeding period to prevent it from becoming excessively long due to high temperature and high humidity. In dry conditions with multiple fertilizers or low temperatures, the leaves are dark green and stunted; under low temperature and dry conditions, the embryos are short and the cotyledons are small, resulting in rigidified seedlings. Therefore, in general, it is not suitable for seedlings. Germination should be carried out under cool, light conditions.
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