Seedling method and time of lettuce

Raising seedlings is a stage that every kind of vegetable must go through. Good seedlings can help plants grow and develop better. So what kind of way should be adopted to grow lettuce, and when should lettuce be planted at a more appropriate time?

Seedling method and time of lettuce

The general sowing time of lettuce is from August to February of the following year, and it is suitable for sowing from mid-October to mid-December, and it can also be sown in early March and early July, but the growth period is short and the yield is low. It was cultivated in greenhouse or small shed in winter and early spring, and in sunshade net or shade shed in summer. Every 60 square meters, 1500 kg of rotten farm manure and 20 kg of superphosphate were applied to the seedling field, and then mixed and leveled evenly after ploughing. Seedling transplanting per mu of cultivated field requires a seedbed of 2030 square meters and a seed amount of 25,30g. When sowing in high temperature season, the seeds must be germinated at low temperature, soaked in well water for about 6 hours, scrubbed, wrapped with wet gauze, and germinated at 15 ℃ ~ 18 ℃. Pour enough water into the seedling bed before sowing, mix the seeds with the same amount of wet fine sand and sow them, cover them with about 0.5 cm thick, 2-3 true leaves and time seedlings to form seedlings.

Growth habits of lettuce

Lettuce likes cold environment and is neither cold-resistant nor heat-resistant. The suitable temperature for growth is 15-20 ℃, and the growth period is 90-100 days. The seeds were tolerant to low temperature and could germinate at 4 ℃. The optimum temperature for germination was 18-22 ℃, and almost no germination was found when the temperature was higher than 30 ℃. During the growth period, I like the cool climate, and 15-20 ℃ is the most suitable for growth, with high yield and good quality. The growth is poor when the temperature is higher than 25 ℃, but the cold tolerance is also strong. 0 ℃ or even short-term sub-zero low temperature does not hinder the growth. The root system is developed, the leaves are waxy, and the drought tolerance is quite strong, but cultivated on fertile and humid soil, the yield is high, the quality is good, and the soil pH value is 5.8-6.6.

The main producing areas of lettuce

Lettuce originated in the Mediterranean coast of Europe. In the past, lettuce was rarely cultivated in China, but mostly in the south. With the reform and opening up and frequent foreign exchanges, the planting area of lettuce has gradually increased in some big cities and coastal open cities in the past 10 years, and then many inland cities have also introduced trial planting, which is welcomed by consumers. Recently, lettuce has become a fast-growing green leaf lettuce in China. It is cultivated in most of the southeast coast of China.

Field management technology of lettuce

1. Watering: the times of watering should be mastered according to the soil moisture and growth after slowing down the seedlings. Usually water for 5-7 days. When the temperature is low in spring, the amount of water should be small and the date of watering interval should be long; in the peak growth period, it is necessary to keep the soil moist; after the leaf ball is formed, watering should be controlled to prevent uneven water from causing crack ball and rotten heart; when the protected cultivation begins to bear balls, watering should not only ensure the plant's need for water, but also should not be excessive, and the humidity in the field should not be too high to prevent diseases.

2. Intertillage weeding: after planting slow seedlings, intertillage weeding should be carried out to enhance soil permeability and promote root development.

3. Topdressing: it is mainly based on base fertilizer, which can not be topdressing in the early growth stage when the bottom fertilizer is full, and at the beginning of heading, nitrogen fertilizer is applied once with water to promote leaf growth; in 15-20 days, nitrogen, phosphorus and potassium compound fertilizer is better, using about 15-20 kg per mu; when the heart leaf begins to curl inward, the compound fertilizer is applied again, about 20 kg per mu.

The specific details of lettuce breeding are very critical, and each link is related to the final growth and development of lettuce. In addition, lettuce has been planted for a long time, and it can be sown and sprouted for a long time, so the key points that we need to pay attention to in planting lettuce in different periods should be different.