How to grow lettuce in a greenhouse? Key points on transplanting, watering, fertilizing and disease prevention

Lettuce

    1. Get the transplanting time right.Lettuce is generally raised as seedlings around the Autumn Equinox of the previous year and transplanted at the Start of Winter. The stem of lettuce keeps elongating and swelling as the plant grows. If transplanted too early, the stem contains too much water and is prone to freezing damage. If transplanted too late, the nutrients absorbed in the early stage cannot supply the needs of lettuce growth through winter.

    2. Watering frequency and method.From transplanting in the previous year to harvest the following year, watering four times is enough for lettuce. The first watering is done after transplanting, the second is the freezing water; after the freezing water is applied, cover the beds with discarded straw mats to provide insulation and ensure the lettuce overwinters smoothly. The last two waterings are done the following year after the Start of Spring, once temperatures rise and the arched shed is put up, up to about 10 days before harvest.

    3. Topdressing.With each watering, apply 60-70 jin of high-potassium compound fertilizer. First, it helps the heads swell; second, it prevents the excessive use of high-nitrogen compound fertilizer from making the upper leaves of the lettuce grow too large and form a closed canopy, which increases the chance of disease.

    4. Disease prevention.Lettuce has few diseases. After the arched shed is put up, ventilate every day to reduce humidity inside the shed and lower the incidence of disease. Once temperatures rise, the plastic film is no longer needed. In routine management, spray chlorothalonil, azoxystrobin or zhongshengmycin every 10-15 days to prevent disease.