Lettuce cultivation in the open air overwintering in Shandong

Lettuce, also known as celery , prefers a cool climate and is slightly resistant to frost. The most suitable temperature for its growth is 15-20℃ during the day and 12-15℃ at night. In Shandong, the planting time of lettuce is relatively flexible. Below, I will introduce the open-air wintering lettuce planting in Shandong. Let’s take a look.

1. Planting time

The time for planting open-air winter lettuce in Shandong area is usually chosen in autumn, specifically between September and October. The temperature during this period is suitable, which is conducive to the germination of lettuce seeds and the growth of seedlings. After planting, lettuce can safely overwinter in the winter of that year and be harvested in April to May of the following year.

2. Variety selection

Selecting lettuce varieties suitable for outdoor overwintering is an important part of the planting process. High-quality varieties that are high-yielding, cold-resistant, and resistant to diseases and insects should be selected, such as "Donglv" and "Dongyang". These varieties have strong cold resistance and adaptability, and can maintain good growth in cold winters.

3. Land preparation and fertilization

Choose land with loose, fertile and well-drained soil for planting. When preparing the land, you need to plow the soil first and apply enough base fertilizer. Well-rotted organic fertilizer or compound fertilizer can be applied to increase soil fertility and ensure that lettuce gets enough nutrients during the winter growing period.

4. Sowing method

Lettuce is usually planted by direct seeding or transplanting. When sowing, the seeds should not be sown too deep. The sowing depth should be 0.5~1.0 cm to ensure that the seeds can germinate under suitable conditions.

5. Seedling management

Maintain suitable temperature and humidity, with daytime temperature at 18~22℃ and nighttime temperature not lower than 10℃. Keep the soil moist, but avoid standing water to prevent disease. Usually, it takes 20 to 30 days to grow lettuce seedlings, and they can be transplanted when the seedlings are 10 to 15 cm tall.

6. Planting time

The time for transplanting is generally chosen before the arrival of autumn frost, in late September to early October. This ensures that the lettuce has enough time to adapt to the environment and successfully survive the cold winter.

7. Planting method

The day before transplanting, keep the soil in the bed moist and cover it with plastic film. The seedlings should be covered with more soil to minimize root damage. Transplanting should be done on a sunny day, and the planting depth should be enough to bury the roots completely in the soil. Not too deep to press down the heart leaves, and the soil should be slightly compacted to ensure that the roots are in full close contact with the soil. The plant spacing should be kept at 25-30 cm and the row spacing at 60-70 cm.

8. Field management

After watering thoroughly for planting, till the soil to retain moisture and slow down the growth of seedlings to ensure that the plants are not affected by drought. After watering the seedlings, the frequency of watering should be determined according to the soil moisture conditions and growth conditions. Generally, water once every 5 to 7 days. In terms of fertilization, for stem lettuce, topdressing should be done by applying 30% to 40% decomposed human and animal manure, 3000 to 4000 kg per mu, 1 to 2 times. It is generally not suitable to apply top dressing to overwintering lettuce.

The above is an introduction to the cultivation of open-air overwintering lettuce in Shandong. The harvest period of overwintering lettuce is usually 60-80 days after planting. Lettuce grows slowly in winter, but it has strong cold resistance, so the harvest period can be appropriately delayed.