The latest course of lettuce planting techniques and methods

Lettuce is commonly known as leaf lettuce, also known as goose lettuce, shipping mark lettuce, lettuce, etc., belongs to the Compositae lettuce genus annual or biennial herbaceous crops, native to the Euro-Mediterranean coast, domesticated from wild species, and has a long history of being introduced into China. There is a lot of cultivation along the southeast coast, especially in the suburbs of big cities and Guangzhou, which is of great planting value. Let's take a look at the planting techniques of lettuce.

Growth habits of lettuce

Lettuce likes cold environment and is neither cold-resistant nor heat-resistant. The suitable temperature for growth is 15-20 ℃, and the growth period is 90-100 days. The seeds were tolerant to low temperature and could germinate at 4 ℃. The optimum temperature for germination was 18-22 ℃, and almost no germination was found when the temperature was higher than 30 ℃. During the growth period, I like the cool climate, and 15-20 ℃ is the most suitable for growth, with high yield and good quality. The growth is poor when the temperature is higher than 25 ℃, but the cold tolerance is also strong. 0 ℃ or even short-term sub-zero low temperature does not hinder the growth. The root system is developed, the leaves are waxy, and the drought tolerance is quite strong, but cultivated on fertile and humid soil, the yield is high, the quality is good, and the soil pH value is 5.8-6.6.

Variety selection of lettuce

1. Heading lettuce: the main characteristics of heading lettuce are that the terminal leaf forms a leaf ball, the leaf blade is entire, serrated or deeply parted, the leaf surface is smooth or wrinkled, and the terminal leaf forms a leaf ball, round or round. The main varieties are Dahu 659, avant-garde 75, Salinas, Beishan 3, Mamick, green and so on.

2. Wrinkled leaf lettuce: the main characteristics of wrinkled leaf lettuce are non-heading, basal leaves, long oval leaves, long petiole, wavy or deeply cracked leaf margin, wrinkled leaves and clustered leaves like large flowers. the main varieties are "Hongfan" purple leaf lettuce, safflower leaf lettuce, green wave, Dongshan lettuce and so on.

3. Upright lettuce: the main characteristics of upright lettuce are long and narrow leaves, upright growth, entire or serrated leaves, thick leaves, thick meat, poor flavor, few varieties, not wide distribution area, and rarely planted in China.

Seedling raising techniques of lettuce

1. Select and sow improved varieties: choose suitable varieties according to needs, such as glass lettuce, emperor, Caesar, heading lettuce, mosaic lettuce, Dahu 659 and so on.

2. Prepare the seedbed: the sandy loam with good water and fertilizer conservation and fertile soil should be selected for lettuce seedling. Bed and soil preparation: 10 square meters of seedling bed with rotten organic fertilizer 10 kg, ammonium sulfate 0.3 kg, calcium superphosphate 0.5 kg, potassium sulfate 0.2 kg, fully mixed evenly to lay Harrow fine, pour enough bottom water, sow seeds after water infiltration.

3. Sowing and raising seedlings: in order to sow evenly, the seeds can be mixed with a small amount of fine sand, covered with 0.3 cm thick tidal soil after sowing, and covered with plastic film to keep moisture. The sowing rate is 30,50g per mu. When the seedlings begin to be unearthed, the plastic film on the border should be opened in time to prevent overgrowth. The suitable temperature of seedling bed should be controlled at 18 ℃ ~ 20 ℃ in daytime and 12 ℃ ~ 14 ℃ at night. Pay attention to ventilation and shade in case of strong light exposure. When the seedlings grow to 2-3 true leaves, the seedlings are divided according to the row spacing of 6-8 cm, and when they grow to 4-5 true leaves, they can be planted, and there is generally no shortage of water at the seedling stage.

Planting management of lettuce

1. Scientific fertilization: lettuce requires clayey loam rich in organic matter and strong water and fertility conservation, lettuce likes slightly acidic, and the soil pH value is 5-7. For every 1000 kg of lettuce, it is necessary to absorb 2.5kg of nitrogen, 1.2kg of phosphorus and 4.5kg of potassium, among which heading lettuce needs more potassium. Nitrogen, phosphorus and potassium fertilizers should be used together during the growing period. The land where lettuce is planted should be ploughed deeply and carefully. Before planting, sufficient basic fertilizer should be applied, and 3000-3500 kg per mu of rotten farm manure should be applied. Turn deeply after application, pour enough bottom water, and make the border after seeing it dry.

2. Careful planting: the seedling bed was irrigated one day before planting to make the seedling moist, and the seedlings started the next day with as much soil as possible to reduce root damage. When planting, first open the ditch on the border surface, the ditch depth is 4cm 6 cm, plant 3 rows on the border surface 70 cm, apply the ternary compound fertilizer according to 25 kg per mu, then irrigate, put the seedlings to cultivate the soil and seal the ditch according to the plant distance of 24 cm, rake the border surface, cover the plastic film, and introduce the seedling out of the film.

3. Post-planting management: lettuce likes to be wet, and sufficient water supply is required during the whole growth period. Slow seedling water was irrigated once after planting for 5-7 days. After watering the seedlings, the plots without plastic film were ploughed and loosened for two times to weed. After watering 3-4 times, combined with watering, nitrogen and phosphorus fertilizer was applied by stages, 15-20 kg per mu. Stop watering before harvest to facilitate storage and transportation.

4. pest control: the main diseases of lettuce are downy mildew, soft rot, virus disease and Sclerotinia sclerotiorum, among which Sclerotinia sclerotiorum and soft rot are more harmful, so rotation can be adopted, planting density should be reduced appropriately, watering should not be too much, shallow hoe should be often done, soil surface should be kept dry, diseased plants should be pulled out in time, withered leaves can be removed and burned, agricultural streptomycin and benzoammonium can be sprayed after the disease. Spray chlorothalonil every 5 to 7 days in high temperature and humidity season for preventive purposes. Insect pests are mainly aphids, thrips, ground tigers, etc., with omethoate, quick kill and other control.

5. Scientific harvest: non-heading lettuce can be harvested timely according to the market price. It is better to harvest lettuce after the leaf ball is tight, and the yield will be affected too early. If it is too late, the stem in the leaf ball will elongate and the quality of the leaf ball will decrease.