Cultivation technology and management methods of head lettuce (how many days does the growth cycle of head lettuce last)

1. Site selection and land preparation

Head lettuce likes light, so the planting plot needs to have enough sunlight, as long as there are no big trees or other obstructions around. Head lettuce is not drought-tolerant or waterlogged, so the plot must have good drainage and irrigation conditions.

After selecting a good plot of land, the land should be deep plowed to a depth of about 20-25 cm. While deep plowing the land, organic fertilizer can be applied as base fertilizer. The amount of organic fertilizer used is about 1500-2000 kg per mu.

In addition, in order to facilitate irrigation and drainage, beds can be used for planting, with a bed width of 55-60 cm, a ditch width of 30-40 cm, and a ditch depth of 25-30 cm.

2. Seedling cultivation

Cabbage lettuce is mostly planted by seedling transplanting. Before sowing, the seeds must be germinated first. First, soak the seeds in warm water for a few minutes. The water temperature should not exceed 30 degrees.

After that, take out the seeds, wrap them in a wet cloth, and place them in an environment of 15-20 degrees for germination. Generally, it will take 2-3 days for the seeds to germinate when more than 80% of them are white .

Seedlings can be grown in seedling cups or seedling trays. The seedling medium can be a mixture of garden soil, compost, and rice husks. 2-3 seeds are planted in each hole, and then covered with fine soil. Water thoroughly, cover with straw to keep moisture, and then place in a greenhouse or greenhouse to wait for germination.

3. Seedling Management

The suitable germination temperature of cabbage lettuce is between 15-20 degrees, and the maximum temperature should not exceed 28 degrees, otherwise it will not germinate.

Under the right temperature, the seeds will germinate after a few days. After germination, you can uncover the straw and allow them to receive appropriate amounts of sunlight to promote seedling growth.

When watering afterwards, you should control the water content appropriately to promote the growth of the root system. About 15 days after sowing, you can water the seedlings with dilute urea water to promote the growth of the seedlings. Thinning should be carried out when the seedlings have 2-3 true leaves.

Proper ventilation should be provided for seedling hardening 3-5 days before transplanting to improve the seedlings' ability to adapt to the environment.

4. Transplantation

25-30 days after sowing, when the lettuce seedlings have 4-6 true leaves, they can be transplanted. The seedlings need to be hardened for 3-5 days before transplanting. Before transplanting, water the seedbed or seedling tray thoroughly to prevent the roots from being damaged when the seedlings are removed.

Cabbage lettuce can be planted in double rows, with a plant spacing of 30-40 cm and a row spacing of about 30-35 cm, with 4000-5000 plants per acre. Transplanting can be done while drilling holes, and seedlings should not be exposed to the sun for a long time outdoors.

The hole depth should not be too deep, just enough to bury the seedlings. After all the transplanting is completed, water the roots once, and after 3-5 days of seedlings acclimatization, normal watering and fertilization can be carried out.

5. Water and fertilizer management

1. Fertilization

The growing period of cabbage lettuce is long, and it needs to be top-dressed several times during the growing period. The first topdressing should be done about 4-6 days after planting. First, quick-acting nitrogen fertilizer can be used to promote the growth of leaves and roots.

After that, you can apply light fertilizer every 7-10 days after watering. The amount of topdressing should not be too much, generally 4-5 kg ​​per mu is enough.

After the head lettuce forms a head, use 20 kg of compound fertilizer and 7.5 kg of potassium fertilizer per mu. Dig a shallow trench between two rows and apply the fertilizer into it, then cover it with soil. Water it after fertilizing, and the amount of water should be enough to keep the soil moist.

2. Watering

Head lettuce is neither cold-resistant nor frost-tolerant. Water thoroughly once after transplanting, and water again 3-5 days after the seedlings have finished acclimatizing.

Watering is generally done in the furrow, allowing the water to slowly penetrate into the roots. Do not water directly on the bed surface to prevent soft rot. Later, you can combine fertilization and water every 7-10 days until harvest.

6. Pest and disease control

The main diseases of head lettuce include downy mildew and soft rot, and the insect pests include aphids and leafminers. Early detection and early treatment are necessary to prevent the diseases and pests from continuing to expand and increase the difficulty of prevention and control.

For downy mildew, you can spray with 600 times solution of thiophanate-methyl wettable powder or 700 times solution of alum wettable powder.

Soft rot can be controlled by spraying 3000-4000 times solution of agricultural streptomycin.

Aphids can be controlled with antworm forest or acetamiprid; leafminers can be controlled with avermectin emulsifiable concentrate.

7. Harvest

Different varieties of lettuce have different harvesting times and different growth cycles. Early-maturing varieties can be harvested in about 55 days, mid-maturing varieties need about 65 days , and late-maturing varieties need 75-85 days . Do not wait until they are fully mature to harvest, but harvest when they are 80-90% mature.

The standard for harvesting is generally determined by experience. There is a simple judgment standard: press both sides of the autumn leaf with both hands, and it can be harvested when it feels firm and not soft.

Water can be properly controlled half a month before harvest, but the leaves fall tightly. Generally, it is sold in time after harvest, and the suitable storage and transportation temperature is 1-5 degrees, which can prolong the storage time.