Chinese name
Lettuce; lettuce
Another name
Glass dish
Latin scientific name
Lettuce? var。 ? Ramona. Holt.
Binomial nomenclature/system
lettuce
boundary
plant kingdom
door
Vascular endothelial cell
summary
Magnolia
subclass
Chrysanthemum subclass
eye
chrysanthemum
The branch of academic or vocational research.
composite family
nationality
Lettuce family
belong to
Lettuce; lettuce
grow
Lettuce; lettuce
Distribution area
It is cultivated in Europe, America, East Asia and most areas along the southeast coast of China.
Sexual taste
Cool and sweet.
morphological character
Lettuce is an annual or biennial herb with a height of 25- 100 cm. The roots extend vertically.
The stem is erect and solitary, with panicle branches on the upper part, and all the stems and branches are white. Basal leaves and lower stems and leaves are large, undivided, oblanceolate, oval or ovoid, 6- 15cm long and 1.5-6.5cm wide, with sharp tips, short cones or circles, no stalks, a heart-shaped or arrow-shaped semi-embracing stem at the base, wavy or serrated edges, and tapering upward, which are the same as those of basal leaves and lower stems and leaves.
The heads are numerous or extremely numerous, arranged in panicles at the top of stems and branches. The involucre is ovoid, with a length of 1. 1 cm and a width of 6mm. The involucral bract has five layers, the outermost layer is triangular, about 65438±0mm long and 2 mm wide, the outer layer is triangular or lanceolate, about 5-7 mm long and 2 mm wide, the middle layer is lanceolate to ovate-lanceolate, about 9 mm long and 2-3 mm wide, and the inner layer is linear and rectangular, about 65438±0cm long and 2 mm wide. All involucral bracts are sharp at the top. Lingual florets are about 15. Achene is oblanceolate, 4 mm long, 65438 0.3 mm wide, flat, light brown, with 6-7 veinlets on both sides, and the tip is sharp and filiform, about 4 mm long, almost as long as achene. The crown hair is 2 layers, slender and slightly rough.
The flowering and fruiting period is from February to September.
Growth habit
Lettuce likes cold environment, neither cold nor heat. The suitable growth temperature is 15℃-20℃, and the growth period is 90- 100 days. Seeds can tolerate low temperature and germinate at 4℃. The optimum germination temperature is 18-22℃, and almost no germination occurs above 30℃.
Plants like cold climate during their growth, and the optimum growth temperature is 15-20℃, with high yield and excellent quality. When the temperature continues to be higher than 25℃, the growth is poor, the leaves are coarse and old, and the leaves are slightly bitter. However, the cold tolerance is also quite strong, and even a short-term sub-zero temperature of 0℃ will not cause great obstacles to growth.
Lettuce has developed root system, waxy leaves and strong drought tolerance, but it has high yield and good quality when cultivated in fertile and humid soil.
The suitable pH value of soil is 5.8-6.6.
geographical distribution
Originated in the Mediterranean coast of Europe, it is widely cultivated all over China.
Main categories
Lettuce can be divided into head lettuce, wrinkled lettuce and upright lettuce according to the growth form of leaves.
Folding lettuce
The main feature of lettuce is that its terminal leaves form leaf bulbs. The leaves are entire, serrated or deeply parted, smooth or shriveled, and the terminal leaves form small beads, which are round or eccentric. The main varieties are Hu Da 659, Qianwei 75, Sa Lin Nasi, Beishan No.3, Mamik and Green.
Folding wrinkled lettuce
The main feature of wrinkled lettuce is that it does not ball. Basal leaves, oval leaves, long petioles, wavy or deeply divided leaf margins, shriveled leaves, and clustered leaves like big flowers. The main varieties are "Hongfan" purple leaf lettuce, safflower leaf lettuce, green wave lettuce and Dongshan lettuce.
Folding upright lettuce
The main characteristics of erect lettuce are long and narrow leaves, upright growth, full or serrated leaves, thick leaves, coarse meat and poor flavor. This variety is rare, not widely distributed and rarely cultivated in China.
cultivation techniques
Folding selective sowing improved varieties
Appropriate varieties should be selected according to needs, such as glass lettuce, emperor, Caesar, head lettuce, mosaic lettuce, Hu Da 659, etc.
Folding preparation seedbed
Lettuce seedlings should be planted in sandy loam with good water and fertilizer conservation ability. Soil preparation for seedbed: 10 square meter seedbed is made of decomposed organic fertilizer 10 kg, 0.3 kg of ammonium sulfate, 0.5 kg of calcium superphosphate and 0.2 kg of potassium sulfate, which are fully and evenly mixed, leveled and raked, filled with water, and sowed after seepage.
Folding sowing and seedling raising
In order to make the sowing uniform, a small amount of fine sand can be mixed into the seeds during sowing, and 0.3-0.5 cm thick moist soil can be covered after sowing, and plastic film can be covered to keep moisture. The sowing amount per mu is 30-50g. When the seedlings begin to be unearthed, the plastic film on the border should be uncovered in time to prevent the seedlings from growing in vain. The temperature of seedbed should be controlled at 65438 08℃-20℃ during the day and 65438 02℃-65438 04℃ at night. Pay attention to ventilation, and keep out the sun when the strong light shines. When the seedlings grow to 2-3 real leaves, divide the seedlings according to the row spacing of 6-8 cm. When the seedlings grow to 4-5 true leaves, they can be planted. Generally, there is no shortage of water and no watering at seedling stage. To prevent seedling diseases, 1-2 times 600 times 75% chlorothalonil solution can be sprayed.
Folding scientific fertilization
Lettuce needs clay loam with rich organic matter and strong water and fertilizer retention ability. Lettuce is slightly acidic, and the suitable soil pH is 5-7. Every 1000 kg of lettuce should absorb 2.5 kg of nitrogen, 0.2 kg of phosphorus/kloc-0 and 4.5 kg of potassium. Among them, lettuce needs more potassium. Nitrogen, phosphorus and potassium fertilizer need to be used together during the growth period. The field where lettuce is planted should be intensively cultivated. Before planting, sufficient base fertilizer should be applied, and 3000-3500 kg of decomposed farmyard manure should be applied per mu. After daubing, turn it deep, water the soles of your feet, and dry it as a border.
Folding and careful planting
Irrigate the seedbed one day before planting to make the seedlings moist, and borrow as much soil as possible the next day to reduce root damage. When planting, first ditch the border with a depth of 4-6 cm, and plant three rows at the border with a depth of 70 cm. After ditching, apply 25 kilograms of ternary compound fertilizer per mu, and then irrigate. After water seepage, put the seedlings at a spacing of 24 cm, cultivate the soil to seal the ditch, level the border, cover it with plastic film, and lead the seedlings out of the film.
Post-planting management after folding
Lettuce likes humidity, and it needs sufficient water supply throughout the growing period. After planting for 5-7 days, irrigate with slow seedling water 1 time. After watering the seedlings slowly, turn over the uncovered plots twice and loosen the soil to weed. After that, water is poured for 3-4 times, and nitrogen and phosphorus fertilizers are applied by stages in combination with watering, and 15-20kg is applied per mu. Stop watering before harvesting to facilitate storage and transportation.
Folding scientific harvesting
Lettuce without heading can be harvested by camera according to the market price. It is best to harvest lettuce with close leaves. If it is too early, the output will be affected. If it is too late, the stems in the leaves will be elongated, the leaves will become loose and the quality will be reduced.
Cultivation of lettuce in folding greenhouse in winter
To plant broccoli in winter, we should first choose varieties with wide applicability and strong cold tolerance, sow them on pre-prepared seedbeds or raise seedlings in nutrient pots. 20-25g seeds per mu.
1. Preparation before sowing: Broccoli can be planted in seedbed or floated for seedling. The substrate and nutrient solution of floating seedling are the same as that of flue-cured tobacco seedling; A loam plough with convenient irrigation and drainage should be used for seedling raising in seedbed, and it should be fully aired, and the width of the border should be 1. -1.8 m, the height of seedbed is 20-25 cm, and decomposed organic fertilizer10-15 kg and a certain amount of phosphorus and potassium fertilizer are applied to every square meter of seedbed.
2. Sowing: Seedbed seedling, that is, seeds are mixed with a certain amount of fine sand in advance before sowing, and the sowing amount is 4-5g per square meter (that is, 5 square meters of seedlings can be planted on one acre of land). After sowing, cover with 0.5- 1cm thin soil, and spray new high-fat film 800 times (spray new high-fat film 800 times to keep moisture, prevent evaporation, prevent sun and drought, keep warm and prevent freezing, and prevent soil layer). ) and then cover it with a thin layer of straw. It is hot and rainy in late summer and early autumn. Whether floating seedlings or seedbed seedlings, they should be covered with sunshade nets to prevent sun and rain.
3. Seedling management after sowing: Pay attention to watering after sowing and keep the soil moist frequently. Seedbed seedling can be raised for about 3 days, and the straw should be uncovered in time. When raising seedlings in summer, special attention should be paid to the prevention and control of yellow striped flea and cabbage caterpillar. Remove the sunshade net 7- 10 days before transplanting, and let the seedlings fully see the light and harden. After 30 days of sowing, the plant height of the seedling is about 15 cm, and it can be planted when there are 5-6 true leaves. Spraying pesticides and fungicides on the seedbed once before sowing, and spraying 800 times of new high-fat film in time after setting the value can effectively prevent evaporation of water on the ground and transpiration of seedlings, isolate pests and diseases, shorten the slow seedling stage, quickly adapt to the new environment and grow healthily.