Native to the Mediterranean coast, lettuce was introduced to China in the 5th century AD and has been cultivated in China for more than 1500 years. The fleshy stems of lettuce are fat and nutritious, and they are a favorite food on many people's tables.
Lettuce has a strong adaptability to the environment and is cultivated in all parts of the north and south of China, but people will find that lettuce grows very "thin" when planting lettuce, and the quality and yield are very low, so how to grow long and thick lettuce? My family has a large piece of lettuce, and I have a lot of experience in the cultivation of lettuce, and today I will share the secret of the high yield of lettuce to you.
Lettuce has a shallow root system, and loose sandy loam soil should be used for planting lettuce. If the soil is too sticky, it will affect the respiration of the root system, the ability of the root system to absorb nutrients will be reduced, and the growth rate of lettuce will be slower.
Note: Lettuce is more sensitive to the acidity and alkalinity of the soil, and it likes to grow in weakly acidic soil, so we should avoid sprinkling a large amount of grass ash when planting lettuce (when the humidity in the field is large, you can sprinkle an appropriate amount of grass and wood ash to dehumidify), the grass ash is alkaline, and the application into the soil will cause the lettuce metabolism to be abnormal.
After transplanting, robust lettuce seedlings have the characteristics of high survival rate, slow seedlings, vigorous growth, and strong resistance to diseases and insect pests, and cultivating strong seedlings is the key to high yield and high quality of lettuce.
Seedbed We can choose a soil with high organic matter content and convenient drainage and irrigation, and then apply 5 kg of fully decomposed farm manure and 0.06 kg of ternary compound fertilizer per square meter of soil as seedling fertilizer, and the soil is leveled and fine, and the soles of the feet are watered. In order to prevent sowing too densely, we can mix the seeds with fine soil for sowing, and use a tooth rake to gently rake the topsoil or cover 0.5 cm after sowing.
Lettuce seeds are generally 5 to 7 days after sowing, and when the seedlings grow 2 true leaves, they can be watered with decomposing thin manure water to promote the growth of seedlings. In order to make the seedlings have sufficient water, nutrients and sunlight, for overly dense seedlings, we also need to carry out inter-seedlings, so that the seedling spacing is maintained at 4 to 5 cm, which is conducive to cultivating strong seedlings.
Note: The seeds of lettuce have a heat dormancy mechanism, and we can soak them in cold water for 8 hours before sowing (if sown in the summer, we can put the soaked seeds in the refrigerator for another 12 hours, which is conducive to breaking the heat sleep mechanism). The most suitable temperature for the germination of lettuce seeds is 15 ~ 20 ° C, after soaking the seeds, we can wrap them in wet gauze and put them in a cool place for germination, keep the gauze moist during the period, generally after 3 days when the seeds are 70% white, they can be sown.
Lettuce is a fertile crop, and on poor soil, lettuce will grow weaker. We can combine the application of 4,000 kg of fully decomposed farmhouse fertilizer and 40 kg of ternary compound fertilizer per mu of land preparation as base fertilizer.
Farm manure is not only comprehensive in nutrition and long-lasting in fertilizer efficiency, but also improves the soil and is conducive to the development of lettuce root system. As the saying goes, "people should not grow, vegetables should not grow fertilizer", farm manure must be fully decomposed before it can be applied, uncorrupted farm manure is not only easy to cause plants to burn roots, but also contains germs and insect eggs that can easily lead to lettuce disease and insect pests.
Although the lettuce seedling stage requires less fertilizer, it requires comprehensive nutrition. Lettuce has the greatest demand for nitrogen in the entire growth period, followed by potassium and least phosphorus, nitrogen can promote the development of lettuce stems and leaves, potassium can promote the synthesis and transportation of carbohydrates, phosphorus can promote the development of roots, and can improve the taste of lettuce.
When the lettuce seedlings emerge 25 days after they emerge, they can be colonized (5 to 7 leaves), and the seedbed is watered thoroughly before colonization to facilitate the emergence of seedlings. When colonizing, the plant spacing is controlled at 25 cm, the row spacing is controlled at 30 cm, the colonization depth is buried in the base of the petiole of the first leaf, and the soil is watered thoroughly after colonization to facilitate the slow seedlings.
Note: Colonization should be carried out in the afternoon or on a cloudy day, if the sunshine is strong, we can build a shade net to speed up the seedlings.
Lettuce likes nitrogen fertilizer, nitrogen deficiency will lead to plant dwarf, weak growth, we can in the lettuce slow seedling logistics water rotting dilute manure water (1000 ~ 1500 kg per acre watering), manure is a quick-available nitrogen fertilizer, not only can promote the rapid growth of seedlings, but also can enhance the taste of lettuce.
Lettuce seedlings into the growth period after 20 days of colonization, we can apply 15 kg of urea per mu, and water after topdressing can prevent lettuce plants from being unripe and pumping, so as to promote leaf occurrence and leaf area expansion. In order to promote stem hypertrophy, we can spray another 0.3% concentration of potassium dihydrogen phosphate foliar fertilizer (90 grams of potassium dihydrogen phosphate per acre with 30 kg of water), sprayed every 10 days, sprayed 2 to 3 times continuously, which can significantly increase the yield of lettuce.
Note: Boron deficiency is easy to lead to lettuce hollow, for boron-deficient soil we can spray 0.3% borax 2 to 3 times during the expansion of lettuce stem expansion, spray once every 7 days, can effectively prevent lettuce hollow.
Lettuce has a shallow root system, is not drought tolerant, and it is advisable to keep the soil moist during the growth period, and it can be watered once every 5 to 7 days, and the high temperature season can be watered frequently. The root system of lettuce is not tolerant to waterlogging, so do not accumulate water in the field and keep the rain dry. In the low temperature fog stage, if the humidity in the field is high, we can remove some branches to improve the ventilation and light transmittance of the field, which can reduce the pests and diseases of lettuce.
Note: During the expansion period of lettuce stems, the supply of soil water should be balanced, and if the soil is dry and suddenly watered in large quantities, the outer skin of the lettuce cannot be expanded and cracked.
In summary, lettuce needs to strengthen water and fertilizer management during the growth period and promote rapid stem expansion on the basis of growing good leaves, which is the key to the high yield and high quality of lettuce. Lettuce should be applied nitrogen fertilizer in the middle and middle period before growth, which can prevent the plant from underripe and pump, supplement potassium fertilizer in the middle stage to promote stem expansion, and water evenly throughout the growth period, so that we can grow high-yielding, high-quality lettuce.