What are the seed selection and seedling raising methods for celtuce?

Celtuce is a plant of the Asteraceae family with very strong adaptability; it is generally cultivated mainly in spring and autumn, and its tender stem is the main part eaten. It is now the busy spring farming season, so let's take a look together at what varieties of celtuce there are and how celtuce is raised from seed.

1. What excellent varieties of celtuce are there?

1. Pointed-leaf celtuce

The leaves are lanceolate with pointed tips; the leaf cluster is relatively small, the internodes are relatively sparse, and the leaf surface is smooth or slightly wrinkled, green or purple in color. The fleshy stem is club-shaped, thick at the bottom and thin at the top. It is relatively late-maturing, relatively heat-tolerant at the seedling stage, and can be grown in autumn or overwintering cultivation.

The main varieties of pointed-leaf celtuce include willow-leaf celtuce, Beijing purple-leaf celtuce, Shaanxi pointed-leaf white celtuce, Chengdu pointed-leaf, Chongqing Wannianzhuang, Shanghai pointed-leaf, Nanjing Baipixiang early variety, and others.

2. Round-leaf celtuce

The leaves are long obovate with slightly rounded tips, the leaf surface is rather wrinkled, the leaf cluster is relatively large, the internodes are dense, and the stem is thick (thicker in the middle and lower part, tapering toward both ends). It matures early, is relatively cold-tolerant, is not heat-tolerant, and is mostly grown as overwintering spring celtuce.

The main varieties of round-leaf celtuce include Beijing Jigua celtuce, Chengdu Guasihong, Erbaipi, Erqingpi, Jinan white celtuce, Shaanxi round-leaf white celtuce, Shanghai small round-leaf, large round-leaf, Nanjing Zipeixiang, Hubei Xiaogan celtuce, Hunan Luochui celtuce, and others.

2. Seedling raising time and methods for celtuce

1. Seedling raising time

For spring celtuce, raise seedlings in greenhouses from December to March, and in open fields from mid-February to late March. For summer celtuce, grow in open fields from April to mid-to-late May, and from late May to July use shade net covering, direct sowing, or high-density planting. For autumn celtuce, from July to September use shade net covering for sowing, and raise seedlings for transplanting. For overwintering celtuce, raise seedlings in open fields from October to November.

2. Preparing the seedbed soil

Because the cultivation seasons differ, there are two forms: open-field seedling raising and protected seedling raising. Seedlings can be raised by making beds and sowing directly in the production field, or by using nutrient soil blocks, paper bags, or nutrient pots. The seedbed soil is 50% decomposed horse manure and 50% garden soil; at the same time, add 20 grams of urea and 250 grams of superphosphate per cubic meter of seedbed soil, mix evenly and sieve, then spread it flat on the seedbed to a thickness of 5-10 cm.

3. Seed selection

Leaf-type lettuce includes head lettuce and loose-leaf lettuce, as well as semi-heading curly-leaf lettuce. In production, head lettuce is mostly used, such as the American Queen, Emperor, and Great Lakes 659, Japan's Olympia, and others, which are relatively heat-tolerant and have a shorter growth period.

4. Seed disinfection

Lettuce seeds are small and germinate quickly, so dry seeds are generally sown directly. The seeds are generally only sun-dried for sterilization. If soaking seeds to promote germination, first soak them in cool water for 5-6 hours, then place them under 16°C-18°C conditions with light to promote germination, and they will sprout after 2-3 days.

5. Standards for strong seedlings

Generally, protected seedling raising takes 30-50 days, with 6-7 leaves, relatively many fibrous roots, a dark green and relatively thick stem, large and wide leaves, a plant height of about 15 cm, and no pests, diseases, or mechanical damage. For open-field direct sowing, the seedling age should preferably be 30 days, with 4-6 leaves.

6. Fine sowing

Before sowing, water the seedbed thoroughly; after the water seeps down, scatter a 0.5 cm layer of fine soil, and then sow. Generally, the sowing rate is 5-10 grams per square meter; after sowing, cover with 0.5-0.8 cm of fine moist soil, maintain the soil temperature at 15°C-18°C, and cover with plastic film or straw curtains to retain moisture; they generally emerge after 3-5 days. If raising seedlings in the open field, about 10 days after emergence (1-leaf stage), thinning can be carried out, to the extent that it does not affect seedling growth.

7. Seedling stage management

At the 2-3 leaf stage of lettuce, transplanting can be carried out; a seedling spacing of 6-8 cm is suitable, with 1 strong seedling per nutrient pot or paper bag. Before transplanting, water thoroughly; after planting, cover with soil, and keep the planting depth at the original level. During the slow seedling stage after transplanting, maintain moisture and warmth, with an air temperature of about 20°C being suitable. After the slow seedling stage, frequently cultivate to promote rooting and prevent the adverse effects of excessive humidity and high temperature with abundant rain in summer. During the seedling stage, water should be given lightly and frequently to keep the seedbed soil moist. For seedling raising in summer and autumn, prevent damage from heavy rain washing and high-temperature drought; rain-proof seedling raising and shade-net-covered seedling raising can be used. Generally, cover with a shade net from 8 a.m. to 4 p.m. on sunny days, and uncover the net all day at night or on cloudy days. In dry weather, water frequently in the morning and evening, and topdress with fertilizer along with watering; generally topdress with diluted human manure 1-2 times, or use 0.3% potassium dihydrogen phosphate for foliar topdressing. About 30 days after sowing, the requirements for low temperature and short-day conditions should be met, which can prevent early bolting.

8. Points for attention

Throughout the lettuce seedling raising period, prevent rodent damage and prevent thin, tall, spindly growth caused by high temperature and high humidity. Under drought with excessive fertilizer or low-temperature conditions, the leaf color is dark green and development is poor; under low-temperature and dry conditions, the embryo is short and the cotyledons are small, resulting in stunted seedlings. Therefore, under general conditions, it is not suitable to restrain seedling growth. Germination promotion should be carried out under cool, light conditions.

Do you have anything to add about celtuce seedling raising? Between round-leaf celtuce and pointed-leaf celtuce, which one do you prefer in your area? You are welcome to leave comments and exchange ideas.

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