How to choose lettuce? What are the methods of raising seedlings?

Lettuce is a kind of Compositae plant with strong adaptability, which is mainly cultivated in spring and autumn, and mainly eats its tender stem. Now is the busy season for spring ploughing. Let's take a look at the varieties of lettuce. How to raise seedlings of lettuce?

What are the fine varieties of lettuce?

1. Pointed leaf lettuce

Leaf blade lanceolate, apex pointed, leaf cluster smaller, Internode sparse, leaf surface smooth or slightly wrinkled, green or purple. Fleshy stems clavate, thick at the bottom and fine at the top. It matures later and is more heat-resistant in seedling stage, so it can be cultivated in autumn or overwintering.

The main varieties of pointed leaf lettuce are willow leaf lettuce, Beijing purple leaf lettuce, Shaanxi sharp leaf white bamboo shoot, Chengdu sharp leaf, Chongqing Wannianzhu, Shanghai sharp leaf, Nanjing white skin incense early planting and so on.

two。 Round leaf lettuce

The leaf is long Obovate, the top is slightly round, the leaf surface shrinks more, the leaf cluster is larger, the Internode is dense, the stem is thick (thicker in the middle and lower part, thinning at both ends), the mature stage is early, the cold tolerance is strong, it is not heat-resistant, and it is often cultivated as overwintering spring lettuce.

The main varieties of round leaf lettuce are Beijing crucian carp shoot, Chengdu hanging silk red, two white skin, two green skin, Jinan white lettuce, Shaanxi round leaf white bamboo shoot, Shanghai small round leaf, big round leaf, Nanjing purple skin incense, Hubei Xiaogan lettuce, Hunan gong hammer lettuce and so on.

2. Time and method of raising seedlings of lettuce

1. Seedling raising time

Spring lettuce was raised in greenhouse from December to March and in open field from mid-February to late March. Summer lettuce, cultivated in open field from April to the first and middle of May, covered with sunshade net from late May to July, directly seeded or planted with high density. Autumn lettuce was sown with sunshade net from July to September, and seedlings were raised and transplanted. Overwintering lettuce, raised in the open field from October to November.

two。 Preparation of bed soil

Due to the different cultivation seasons, there are two forms of seedling raising in open field and protected field. Seedlings can be planted in the production field, or they can be raised with nutrient clods, paper bags or nutrient bowls. The nursery bed soil is 50% mature horse dung and 50% garden soil, at the same time, 20 grams of urea and 250 grams of superphosphate are added to each cubic meter of bed soil, and after mixing and sieving, 5 cm to 10 cm thick is laid on the seedbed.

3. Seed selection

Leaf lettuce includes heading lettuce and loose leaf lettuce, as well as semi-heading wrinkled lettuce. The production of multi-purpose heading lettuce, such as empress, emperor and Great Lakes 659 of the United States, Olympia of Japan, etc., is more heat-resistant and the growth period is shorter.

4. Seed disinfection

Lettuce seeds are small and germinate quickly, so they are usually used for dry seed direct seeding. Seeds are usually only dried and sterilized. If soaking seeds to promote germination, soak in cold water for 5 hours for 6 hours, then put them under the condition of 16 ℃ ~ 18 ℃ to see light to accelerate germination. After 2 to 3 days, the buds can emerge.

5. Strong seedling standard

Generally, the seedlings are raised in protected areas for 30-50 days, with 6-7 leaves, more whisker roots, black-green stems, thicker stems, large and wide leaves, plant height of about 15 cm, and no plant diseases and insect pests and mechanical damage. The suitable age of seedling for direct seeding in open field is 30 days, and the seedling has 4 leaves and 6 leaves.

6. Fine sowing

Before sowing, pour enough bottom water on the seedbed, sprinkle 0.5 cm thick fine soil after the water seeps, and then sow seeds. Generally, the sowing rate per square meter is 510g. After sowing, cover fine fluvo-aquic soil 0.5cm-0.8cm thick, keep soil temperature 15 ℃-18 ℃, cover with plastic film or grass curtain to moisturize, generally unearthed after 3-5 days. If the seedlings are raised in the open field, about 10 days after they are unearthed (1 leaf stage), the seedlings can be carried out so as not to affect the growth of the seedlings.

7. Seedling stage management

Lettuce can be transplanted at 2-3-leaf stage, with a suitable seedling distance of 6-8 cm, and 1 seedling per nutrition bowl or paper bag. Pour sufficient bottom water before transplanting, cover the soil after planting, and the depth of planting should be kept at the original level. In the slow seedling stage, it is necessary to keep moisture and keep warm, and the temperature should be about 20 ℃. After slowing down the seedlings, ploughing and promoting roots should be done frequently to prevent the adverse effects of excessive humidity and high temperature and heavy rain in summer. Watering at the seedling stage should be watered with small water frequently to keep the bed soil moist. Summer and autumn seedlings should be protected from rainstorm, high temperature and drought, and rain-proof seedlings and sunshade nets can be used to cover seedlings. Generally sunny day from 8 am to 4 pm to cover the sunshade net, in the evening or cloudy day to uncover the net. Dry weather should be watered frequently in the morning and evening, can be combined with watering topdressing, generally thinning human feces for 1 or 2 times, or 0.3% potassium dihydrogen phosphate foliar topdressing. About 30 days after sowing, the requirements of low temperature and short sunshine should be met, which can prevent early bolting.

8. Matters needing attention

In the whole lettuce seedling period, it is necessary to prevent rodent damage and prevent slender height and excessive growth caused by high temperature and high humidity. Under the condition of drought and fertilizer or low temperature, the leaf color is dark green and underdeveloped; under the condition of low temperature and drying, the embryo is short and the cotyledon is small, resulting in ossified seedlings. Therefore, under normal circumstances, it is not suitable for squatting seedlings. Sprouting should be carried out under cold and bright conditions.

Do you have anything to add about the breeding of lettuce? Which do you prefer, round-leaf lettuce or pointed-leaf lettuce? Welcome to leave a message and communicate with us.

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