Lettuce planting techniques: how to raise seedlings of lettuce?

How do you grow lettuce? Please introduce the method of raising lettuce seedlings in detail, you can refer to the following methods: first, the preparation of bed soil due to different cultivation seasons, so there are two forms of open field seedlings and protected field seedlings. Seedlings can be planted in the production field, or they can be raised with nutrient clods, paper bags or nutrient bowls. The nursery bed soil is 50% mature horse dung and 50% garden soil, at the same time, 20 grams of urea and 250 grams of superphosphate are added to each cubic meter of bed soil, and after mixing and sieving, 5 cm to 10 cm thick is laid on the seedbed. Lettuce seed selection Leaf lettuce includes heading lettuce and loose leaf lettuce, as well as semi-heading wrinkled leaf lettuce. The production of multi-purpose heading lettuce, such as empress, emperor and Great Lakes 659 of the United States, Olympia of Japan, etc., is more heat-resistant and the growth period is shorter. Third, lettuce seed disinfection accelerates germination lettuce seed is small, germinates quickly, generally uses dry seed direct seeding. Seeds are usually only dried and sterilized. If soaking seeds to promote germination, soak in cold water for 5 hours for 6 hours, then put them under the condition of 16 ℃ ~ 18 ℃ to see light to accelerate germination. After 2 to 3 days, the buds can emerge. Fourth, lettuce should be sowed at the right time. Lettuce can be produced all the year round, so it can also raise seedlings with multiple stubble. Lettuce harvested from April to May can be sown and raised seedlings in February and March in spring. For lettuce harvested from May to June, varieties with heat resistance, disease resistance and late bolting should be selected and generally sowed in April. Lettuce harvested from September to October is usually sown from June to July. Lettuce harvested in winter is usually sown in October. It can be produced in solar greenhouse in winter and can be planted after stubble harvesting. In the seeding bed, you can sow seeds at any time, sow one crop a month, plant one crop, harvest one crop, sow, plant and harvest at the same time. 5. The standard for strong lettuce seedlings is generally raised in protected areas for 30-50 days, with 6-7 leaves, more whisker roots, black and green stems, thick stems, large and wide leaves, plant height of about 15 cm, and no plant diseases and insect pests and mechanical damage. The suitable age of seedling for direct seeding in open field is 30 days, and the seedling has 4 leaves and 6 leaves. Sixth, lettuce fine sowing method before sowing, pour enough bottom water on the seedbed, sprinkle 0.5 cm thick fine soil after the water seeps, and then sow. Generally, the sowing rate per square meter is 510g. After sowing, cover fine fluvo-aquic soil 0.5cm-0.8cm thick, keep soil temperature 15 ℃-18 ℃, cover with plastic film or grass curtain to moisturize, generally unearthed after 3-5 days. If the seedlings are raised in the open field, about 10 days after they are unearthed (1 leaf stage), the seedlings can be carried out so as not to affect the growth of the seedlings. 7. The management method of lettuce seedling stage can be transplanted at lettuce 2-leaf 3-leaf stage, the suitable distance between seedlings is 6-8 cm, and 1 seedling can be cultivated in each nutrition bowl or paper bag. Pour sufficient bottom water before transplanting, cover the soil after planting, and the depth of planting should be kept at the original level. In the slow seedling stage, it is necessary to keep moisture and keep warm, and the temperature should be about 20 ℃. After slowing down the seedlings, ploughing and promoting roots should be done frequently to prevent the adverse effects of excessive humidity and high temperature and heavy rain in summer. Watering at the seedling stage should be watered with small water frequently to keep the bed soil moist. Summer and autumn seedlings should be protected from rainstorm, high temperature and drought, and rain-proof seedlings and sunshade nets can be used to cover seedlings. Generally sunny day from 8 am to 4 pm to cover the sunshade net, in the evening or cloudy day to uncover the net. Dry weather should be watered frequently in the morning and evening, can be combined with watering topdressing, generally thinning human feces for 1 or 2 times, or 0.3% potassium dihydrogen phosphate foliar topdressing. About 30 days after sowing, the requirements of low temperature and short sunshine should be met, which can prevent early bolting. Eighth, lettuce seedling precautions in the whole lettuce seedling period to prevent rodent damage, to prevent high temperature and high humidity caused by thin and high growth. Under the condition of drought and fertilizer or low temperature, the leaf color is dark green and underdeveloped; under the condition of low temperature and drying, the embryo is short and the cotyledon is small, resulting in ossified seedlings. Therefore, under normal circumstances, it is not suitable for squatting seedlings. Sprouting should be carried out under cold and bright conditions. Click to get more lettuce planting techniques click to get more vegetable planting techniques