Planting technique of lettuce in greenhouse

Lettuce planted in late autumn is usually on the market in early March after the Spring Festival. Lettuce is on the market at this time, the price is low, the benefit is poor, using plastic greenhouse to cultivate winter lettuce, high yield, good quality, listed during the Spring Festival, remarkable economic benefits, now Xiaobian will introduce the greenhouse lettuce planting technology to everyone.

Pre-planting preparation of lettuce

1. Field selection: continuous cropping of lettuce is avoided, it is better to rotate with Gramineae crops, and paddy soil is generally suitable. The field requires high terrain and convenient drainage and irrigation.

2. Variety selection: select early-maturing varieties that are cold-tolerant and freeze-tolerant. Such as Kexing No. 1, cold-resistant two white bark, cedar, hanging silk red and other varieties of lettuce.

3. Sowing at the right time: generally sowing around 2 days before and after September 10, the amount of seed used per mu needs to sow about 50g, the seedling order is 30ml for 50 days, and the planting period is before October 15th.

Planting buckle film of lettuce

1. Prepare before planting. Dig deep into the Kang soil a week in advance and apply enough base fertilizer at one time. According to 1 mu of rotten organic fertilizer 2500 Mill 3000 kg, Ternary compound fertilizer 150 kg, and then prepare the land, the width of the border is 4 Mui 8 feet.

2. Planting density: the planting row spacing is 40 cm, the plant spacing is 35 cm, and about 5000 plants can be planted per mu.

3. In the middle of December, it has entered the cold winter, and the plant grows slowly and is vulnerable to low temperature freezing injury, which is characterized by dry leaves, dry stems and poor quality. In order to create a good environmental condition for the growth of lettuce, plastic film should be covered immediately to keep warm.

Planting management of lettuce

1. Planting: immediately after planting, 5% human and animal dung water is applied to determine the root. 5Mel applied 10% human and animal dung water and 0.2% urea to lift seedlings once every 7 days, and carried out a soil ploughing. Increase the amount of fertilizer needed when opening a small plate, and add 0.3% urea and 0.3% potassium chloride mixture of livestock dung water every 7 days to promote the early growth of lettuce. At the initial stage of stem expansion, burrowing holes were made between plants and 50g of ternary compound fertilizer and oil-withered mixed fertilizer at 7:3 were applied. After buckling the film, attention should be paid to fertilizer control. The stem fertilizer was applied again from late December to January of the following year, usually with 30% human and animal manure water plus 0.5% urea and 0.5% potassium chloride mixture.

2. Temperature and humidity control in greenhouse: temperature and humidity management is the key technical measure for the success or failure of winter lettuce in greenhouse. According to the needs of plant growth and climate change, it is generally divided into two stages of management: the early stage of anti-high temperature channeling rod is too long. In the later stage, it is mainly heat preservation and anti-freezing, while paying attention to ventilation and dehumidification. Generally, after buckling the film, if the temperature is too high, the edge film should be opened to cool down. Later, as the temperature drops, the edge film will no longer be uncovered. Only open two shed doors to cool down. When it comes to frost and snow, let out the wind and dehumidify every 2 days to keep the air in the shed fresh.

3. Application of growth regulators: after planting slow seedlings, if the temperature is on the high side, the seedlings are easy to flee, they can be sprayed once with 50mg/1 's metoprolol or paclobutrazol solution to control the elongation of internodes. When opening a small plate, spray with 100mg/1 's "481" aqueous solution to increase functional leaves and promote the formation of photosynthates. Spraying 25mg/1 "Shifengle" or 600x "Jintianbao" nutrient liquid fertilizer during stem expansion can further increase the yield and improve the quality.

Disease control of lettuce

Lettuce in greenhouse is susceptible to downy mildew and sclerotia soft rot under the condition of high humidity for a long time. In addition to strengthening the management in the greenhouse, microbial control and chemical control should be combined. Before infection, 500 Mel 600 times "Yi an Shenli" or "Yi Yi Jiu" microbial liquid can be sprayed 3 times to improve the disease resistance of the plant. After infection, downy mildew was sprayed with 70% ethyl manganese 500 times, sclerotia soft rot was sprayed with 50% carbendazim 400 times plus 70% mancozeb 500 times or 50% methyl topiramate 800 times plus 50% promethrin 1000 times. Chlorothalonil aerosol or instant Keling aerosol can also be used for prevention and treatment.