Spring cultivation techniques of lettuce in greenhouse

Lettuce, also known as lettuce, Asteraceae lettuce species can form a variety of fleshy tender stems, herbaceous plants in 2012. Alias stem lettuce, lettuce bamboo shoots, green shoots, lettuce. Delivery period: from January to April. It is native to Central or North China. The aboveground stem is edible, the stem skin is white-green, the stem is crisp and tender, the young stem is emerald green, and turns white-green after maturity. Mainly edible fleshy tender stems, which can be eaten raw, salad, fried, dried or pickled, and tender leaves can also be eaten. Stems and leaves contain lettuce and lettuce. It tastes bitter and has analgesic effect. Lettuce has strong adaptability and can be cultivated in spring and autumn or overwintering, mainly in spring and harvested in summer.

Morphological characteristics of lettuce

The stem looks like a circle, like bamboo shoots. Straight roots, most of the lateral roots after transplantation, shallow and dense, mainly distributed in the 20-30cm soil layer. The stem is shortened. Leaves alternate, lanceolate or oval, etc., light green, green, dark green or purplish red in color, leaves spreading or wrinkled, entire or notched. The shortened stem gradually elongated and thickened with the plant growth. after the stem tip differentiated into flower buds, the stem grew thicker while the flower stem elongated, forming a rod-shaped fleshy tender stem. The flesh is light green, emerald green or yellowish green. Panicle with yellowish flowers, each inflorescence with about 20 flowers, self-pollination and sometimes cross-pollination. Achenes, black-brown or silver-white, with crown hairs.

Growth environment of lettuce

Lettuce is sensitive to the acidity and alkalinity of soil and is suitable for planting in slightly acidic soil. The root system of lettuce is shallow, the absorption capacity is weak, and the demand for oxygen is high. Sand loam and loam are the best soil for planting lettuce.

Spring cultivation techniques of lettuce in greenhouse

Lettuce is a Compositae plant, heat-resistant, cold-resistant, can be cultivated all the year round. The cultivation of lettuce in greenhouse in spring has a short growth period, supplies the market, and has high economic benefits.

Spring lettuce in greenhouse is generally planted in the greenhouse with plastic film in the first and middle of November, the row spacing is 25 cm × 30 cm, and it can be put on the market in mid-February. The cultivation techniques are as follows:

First, temperature and humidity management. In the initial stage of planting, attention should be paid to ventilation and humidity reduction, ventilation should be needed when the temperature is above 0 ℃ at night, small arch shed and grass curtain should be built when the temperature is below 0 ℃, and the grass curtain should be opened during the day. When the stem began to expand to before harvest, the greenhouse temperature during the day 15 ℃ 20 ℃, more than 24 ℃ ventilation, at night should not be less than 5 ℃.

Second, fertilizer and water management. After planting, we should irrigate enough stable root water, slow seedling for 6 days and then slow seedling water. At the same time, we should apply ammonium sulfate 15 kg per mu, and then plough and loosen the soil for 3 times. At the beginning of the group, fertilize once with the water, apply 20 kg of ammonium sulfate per mu, and then continue ploughing and squatting seedlings. When the stem begins to expand, water it in time and follow the water mu to chase the ternary compound fertilizer 25MUR 30kg. The soil should be kept moist after that.

Third, disease prevention and control. At the initial stage of the disease, 800 Mel 900 times of 25% Metalaxyl Manganese Zinc wettable powder and 1500 times of 50% Sukeling wettable powder were sprayed, or mixed with 50% carbendazim glue suspension 500 ml 600 times for 3 times (once every 7 days).

Fourth, harvest. The best harvest time is when the tip of the main stem is equal to the tip of the tallest leaf. In order to be listed in advance, it can be picked early, close big and stay small, and list in batches.