What are the management measures for facility-grown leafy vegetables in winter?

Winter facility-grown leafy vegetables are mainly cold-tolerant and semi-cold-tolerant leafy types, such as baby bok choy and spinach. The management of leafy vegetables in winter greenhouses mainly requires attention to the following aspects:

1. Humidity. Reasonable irrigation is the main measure for regulating humidity in winter greenhouses. Irrigation should mainly consist of light watering, and flooding irrigation should be avoided. Watering should preferably be done between 10 a.m. and 12 noon, so as to coordinate with ventilation to expel excess moisture and reduce the relative air humidity at night. Because the greenhouse environment is enclosed, moisture from soil water and plant transpiration is not easily released, resulting in high humidity inside the greenhouse. To reduce humidity, open ventilation openings appropriately.

2. Temperature. Although leafy vegetables are tolerant of low temperatures, winter greenhouses should still pay attention to heat preservation, maintaining a daytime temperature of 20°C and a nighttime temperature of 5°C. Do not let the temperature get too low, so as to avoid cold damage. If the temperature is too high, it will cause the plants to grow leggy and affect quality. Temperature can be controlled by the timing of uncovering the thermal insulation quilt. Generally, on clear days, uncover the thermal insulation quilt at around 9:30 a.m. and cover it at 16:00 in the afternoon. When there are continuous overcast days lasting 3-4 days or longer, from 11 a.m. to 14 p.m. you should also take advantage of the relatively higher outdoor temperatures around noon to uncover the thermal insulation quilt so the plants receive some scattered light, which is beneficial to plant growth and development.

3. Pest and disease control. In accordance with the principle of "prevention first, integrated control," adhere to giving priority to agricultural control, physical control, and biological control; for chemical control, use the smoke fumigation method, pay attention to rotating pesticides, mix them reasonably, and strictly control the pre-harvest interval for pesticides. Shang Chaoju