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Cultivation techniques and methods of lettuce
Lettuce is one of the vegetables we often eat. How much do you know about the cultivation techniques of lettuce? Let's take a look at the lettuce planting techniques I carefully recommend to you, hoping to help you.

Lettuce planting techniques

Loose soil.

Sprinkle lettuce seeds appropriately according to the size of the land.

After all seeds are sown, water them properly and cover them with a thin layer of soil.

After sowing seeds, they will grow in about 2 weeks. You can water them every three days to make them grow faster.

After all the lettuce grows, you can water it every two days, so it can grow faster.

After the lettuce grows to about 5 cm, some lettuce can be appropriately transplanted according to the density of lettuce and planted in other places.

When transplanting to other places, the best time is around 6 pm, and the spacing between each lettuce is about 10 cm. After planting, you can water it properly, so that the transplanted lettuce is easy to survive.

When the lettuce grows big enough, if you want to eat more lettuce, you don't have to uproot the whole lettuce, just break off the leaves of the lettuce, so you can eat lettuce many times.

Biological characteristics of lettuce

(A) morphological characteristics

Lettuce has shallow and dense roots and well-developed fibrous roots, which are mainly distributed in the 20 cm soil layer on the surface. Short stem, basal leaves alternate on short stem. ※. Leaves are lanceolate, oval, obovate, nearly round, with dark green, emerald green, yellowish green, purplish red and so on. The leaves are flat or shriveled, wavy or lobed, the outer leaves are unfolded, and the heart leaves are loose or folded into leaves. Head flower, pale yellow flower, self-pollination, single room, achene. Lettuce seeds are small, not easy to germinate, and the ability of emergence is weak. The seeds are silvery white or dark brown, with crested hairs, which can be scattered with the wind. The 1000-grain weight is 0.8 ~1.2g. ..

(2) Growth and development

Lettuce is usually transplanted. The root development of lettuce is the most vigorous period within two weeks after germination. The taproot can be up to 20 cm deep, producing more lateral roots. Roots have strong regeneration ability and are suitable for transplantation. After lettuce is planted, leaves grow rapidly under suitable fertilizer and climate conditions. As a non-heading lettuce, the fast-growing leaves become product organs. For head lettuce, after planting, the number of outer leaves increased and the size of outer leaves changed obviously. When the number of outer leaves reaches a certain level and the conditions are suitable, the heart leaves begin to roll, then the number of leaves increases and the leaves expand and enrich. It takes about 30 days for lettuce to be rolled into a leaf ball from the heart. The growth and development cycle of lettuce can be divided into the following periods:

1. From seed germination to cotyledon development, the germination period is about 8 ~ 10 days, and the true leaves are exposed.

2. At the seedling stage, the true leaves contact the clump trees (growth 1 leaf sequence, that is, about 5-6 leaves), the direct seeding takes about 17-27 days, and the seedling transplanter takes about 30 days.

3. The rosette stage, from fruiting to the growth of two leaf sequence rings, and the head lettuce begins to wrap, about 15 ~ 30 days.

4. The organogenesis period of this product is about 30 days from the beginning of wrapping to the formation of leaf bulb.

5. From bolting to fruit ripening, the flowering and fruiting period is about 1 ~ 2 months. Generally, it blooms after bolting, and achenes mature about 15 days after flowering.

(3) Requirements of living conditions

Lettuce is eaten by leaves or bulbs. It is the theoretical basis for cultivating lettuce to understand the demand of lettuce for environmental conditions during the vegetative period. Lettuce prefers cold to high temperature, sunshine, dampness and waterlogging, and has wide adaptability to soil. ※. The fertile sandy loam with good drainage is the most suitable, and the slightly acidic soil with pH around pH6.5 is the most suitable for growth. Therefore, lettuce production technology should provide conditions to meet the needs of lettuce production development according to its biological characteristics, so as to achieve high yield, high quality and high efficiency.

1. temperature ※ Lettuce is a semi-cold-tolerant vegetable, which likes mild and cool climate. It is neither hot nor cold. The suitable temperature range of non-heading lettuce and heading lettuce is different. Wild lettuce has different requirements on temperature at different growth and development stages. Seeds can germinate above 4℃, but germinate slowly. The optimum temperature of seed germination is 18℃ ~ 20℃, and it takes 4 ~ 6 days to germinate. When the temperature is higher than 27℃, the water absorption of seed coat is blocked and the germination is poor. Seeds harvested in summer can't germinate immediately, because high temperature leads to dormancy of lettuce seeds, so it must be stored at low temperature of 0℃ ~ 5℃ to break dormancy, and low temperature and shading measures should be taken in summer sowing. The suitable temperature for lettuce growth period is 15℃ ~ 20℃ in the daytime and 12℃ ~ 15℃ at night. But at the seedling stage of lettuce, it has strong adaptability to temperature. After short-term exercise, the seedlings can endure the low temperature of-1℃ ~-2℃ for a short time and are not afraid of light frost. However, the heat tolerance of seedlings is poor. When the daily average temperature exceeds 24℃, the seedlings grow in vain, resulting in early bolting. Lettuce has a small adaptation range to temperature and is neither cold nor heat-resistant. The suitable daytime temperature at heading stage is 17℃ ~ 20℃. Below this temperature range, the higher the temperature, the greater the leaf growth. Above 25℃, lobules are not easy to form, or the heart leaves are necrotic and rotten due to high temperature in the globules. The flowering and fruiting period requires a higher temperature, which is lower than 10℃. Although it can bloom normally, it will not bear fruit. The higher the temperature is in the range of 22℃ ~ 29℃, the less days are needed from flowering to seed maturity. At the temperature of 19℃ ~ 22℃, the seeds will mature in 10 ~ 15 days after flowering.

2. Moisture ※ Lettuce has shallow root system, large leaf area, high water content and is not drought-tolerant. It requires a uniform and sufficient water supply throughout the growing period. At seedling stage, the soil moisture should be clear between wet and dry, if it is too wet, it will grow white, and if it is too dry, it will age the seedlings. Proper control of water before heading is beneficial to the formation of good root system and strong rosette leaves. Adequate water supply is needed at heading stage, which is easy to cause loosening or non-heading, and at the same time, bitter vegetables in plants increase and bitterness increases. It is not advisable to water the bulb after it is too wet or too dry in the late stage of nodulation, so as to avoid cracking or rot of the bulb, and low air humidity is required. If the air humidity is high, soft rot, Sclerotinia sclerotiorum and other diseases are prone to occur.

3. Illumination ※ Lettuce likes sunshine, avoid shade, seeds germinate quickly under light, and sufficient light is beneficial to plant growth, with vigorous photosynthesis, more nutrients and vigorous growth. Lettuce with balls can bear balls early. On the contrary, on cloudy days or in weak light, the leaves become smaller and slender, and the plants grow weak, which affects the bearing of the ball. In case of high temperature and long sunshine, it is easy to induce flower bud differentiation and lead to early bolting. The higher the temperature, the faster the bolting.

4. Soil and nutrition ※ Under conventional soil cultivation conditions, lettuce needs high soil fertility. Loam or clay loam with rich organic matter, good aeration and water and fertilizer conservation is beneficial to the growth of lettuce. On the contrary, if lettuce is planted in poor soil with poor ventilation and lack of organic matter, the root system will develop poorly and the plant will grow slowly, resulting in small and loose leaves and poor quality. Lettuce is especially suitable for rotation with solanaceae vegetables, because solanaceae vegetables have deep roots and fertile soil.

5. Nutritive lettuce is a kind of green leafy vegetable, and nitrogen supply must be guaranteed at each growth stage, otherwise the leaves will grow slowly and the number of leaves will be less differentiated. Therefore, nitrogen fertilizer should be given priority to, and phosphorus and potassium fertilizer should be properly combined. Phosphorus deficiency at seedling stage not only resulted in fewer leaves, but also short plants and reduced yield. Potassium deficiency has little effect on leaves, but it can affect leaf weight and significantly reduce the leaf bulb weight of lettuce. Therefore, we should pay attention to the coordination and balance of various nutrient elements.

Lettuce variety types

(1) Variety type

Lettuce cultivated and used in production can be divided into two kinds: lettuce with head and lettuce without head. Lettuce is divided into crisp leaves and soft leaves; Non-heading lettuce can be divided into upright lettuce and wrinkled lettuce, and upright lettuce can be divided into round lettuce and pointed lettuce.

1. Common name of lettuce? Lettuce is the main type of lettuce, widely distributed, with many varieties and excellent quality. It is characterized by large, nearly round leaves, green or yellowish green, entire, deeply divided, serrated and other plant types. The leaves are dense and can form obvious bulblets. According to leaf quality, it can be divided into brittle leaves and soft leaves. The crisp-leaf type leaves are slightly wrinkled, crisp, good in quality, tight and not easy to spread. Leaves overlap, and the leaves are spherical, oblate or conical. Soft leaf type has smooth leaves, soft leaves, folded leaves and loose balls.

2. Non-heading lettuce can be divided into upright lettuce and wrinkled lettuce. Erect lettuce, also known as loose leaf lettuce, has long, narrow, upright leaves, which generally do not bear balls or are cylindrical in shape, such as Dengfeng lettuce in Guangzhou. Wrinkled leaf lettuce, commonly known as glass lettuce, can be divided into green leaf variety and purple leaf variety according to leaf color, without heading or loose leaves. For example, soft-tailed lettuce in Guangdong.

(2) Excellent varieties

1. A very early-maturing lettuce variety introduced by the emperor from the United States. The growth period is about 80 days, the leaves are light green, there are many notches on the leaf edge, and the outer leaves are small and few; The leaf bulb is light green, slightly yellow and dense, and the single bulb weighs 400 ~ 500 grams. Crisp and tender, good quality, disease resistance, heat resistance, wide adaptability, bolting very late, suitable for open cultivation in spring and autumn, more suitable for summer cultivation, can be used as a summer lettuce variety. The yield per mu is about 2000 kilograms.

2. Sa Lin Nasi is a medium and early-maturing lettuce variety introduced from the United States. The outer leaves are few, dark green, wavy and coarsely serrated. The leaves are green and white, round and dense, and the weight of a single ball is 400 ~ 500 grams. Good appearance and good quality. Heat resistance is average, suitable for spring and autumn protection and open field and summer shading cultivation. The plant spacing is 30 cm square, and the yield per mu is 6000 ~ 7000 plants, and the yield per mu is 3000 ~ 3500 kg. The mature period is neat, and it is more resistant to transportation. It takes about 50 days from planting to harvesting.

3. Conventional varieties of Caesar lettuce imported from Japan. Very early maturity, compact plant type, neat growth, high and round leaf ball, single ball weighing 400-500 grams, extremely short column in the ball, good quality, strong disease resistance, heat resistance, late bolting and good high temperature nodulation, suitable for open cultivation in summer.

4. Queen's early-maturing lettuce varieties introduced from the United States. The lateral leaves are dark green, with medium-sized leaves and concave margins. The leaf ball is of medium size and compact structure, and the weight of a single ball is 500 ~ 600g g. The growth period is 85 days, the growth is neat, the flavor is good, the bolting is late, and it is more resistant to virus disease and top burning disease. Suitable for open field and protected cultivation in spring and autumn.

Olympia is a very early-maturing lettuce variety introduced from Japan. The lateral leaves are small and few, the leaves are light green, and there are many notches on the leaf edge. The leaf ball is compact and yellow-green, and the single ball weighs 400 ~ 500 grams. The growth period is 65 ~ 70 days. Good quality, strong heat resistance, bolting late, suitable for open cultivation in summer.

6. Hu Da 659 is a middle-late maturing lettuce variety introduced from the United States. Green leaves, many outer leaves, large and dense leaves, and the weight of a single ball is 500 ~ 600 grams. The growth period is 1 10 day, and the yield per mu is 3500 ~ 4000 kg. Good quality, strong cold and heat resistance, suitable for cold and open cultivation in spring and autumn.

7. The varieties of lettuce in Carona were introduced from Holland. Mid-late maturity, bright green leaves, slightly wrinkled, plant height about 25 cm, spreading degree 40 cm; The bulb is15.4cm high and16cm wide, round, white and green, and tightly wrapped. A single ball weighs 700-800g, and it takes 55 days from planting to harvesting. Excellent quality, crisp, tender, slightly sweet and rich in water.

8. Glass lettuce Guangdong peasant varieties. Loose-leaf lettuce, with plant height of 25cm, spreading degree of 27cm, clustered leaves, nearly round, thin leaves, length of18cm, width of17cm, yellow-green luster, wavy leaf margin, shriveled leaves, weight of 200-300g per plant, soft and smooth, heat-resistant and cold-resistant, suitable for cultivation in spring and autumn. Generally, the yield per mu is 2000 ~ 2500 Jin.

9. Dengfeng, Guangdong Province belongs to upright lettuce, also known as long-leaf lettuce. The leaves are long and narrow, wavy and light green, with a plant height of 30 cm, a spreading degree of 36 cm and a plant weight of 330 g, which is suitable for summer cultivation.

10. Local varieties of red lettuce in Panzhihua, Sichuan. It belongs to upright lettuce, medium-ripe, with lateral spreading leaves, spreading degree of about 53 cm, wrinkled leaves, oval shape, purplish red between green, smooth leaf edge and strong heat resistance, and the weight of each plant is about 450 grams.

1 1. Oriental Triumph Beijing Oriental Zheng Da Seed Co., Ltd. Loose-leaf lettuce variety, leaves clustered, erect, plant height 25 cm, spreading degree 30 cm, leaves nearly round, leaves shriveled, yellow-green, shiny and wavy. The weight of a single plant is 300-500g, and the growth period is 50-60 days. Crisp and tender, with moderate moisture. Heat resistance, disease resistance and high yield.

12. Red sail purple leaf lettuce is a loose leaf lettuce variety introduced from the United States by Beijing special vegetables Seedling Company. Early maturity, the whole growth period is 50 days. Light-loving, heat-resistant, not easy to bolting, large plants, wrinkled leaves, purple veins, beautiful colors, with the approach of harvest, red gradually deepened. The yield per mu1000 ~ 2,000 kg is suitable for open field cultivation in spring, autumn and summer and protected cultivation in winter.