With the popularity of off-season vegetables, there's a growing interest in growing them in greenhouses. Constructing greenhouses is relatively simple, and the investment cost is sufficient. However, greenhouse management is not so straightforward.

Thermal Management Techniques for Film Greenhouse: Temperature is one of the key factors affecting crop growth. Adjusting the temperature suitable for crop growth is the primary task in winter greenhouse production and management. There are two methods to regulate greenhouse temperature: one is to enhance the plant's cold resistance, and the other is to utilize the greenhouse's insulation facilities.

1. According to the varying temperature and growth habit requirements of different crops, the corresponding greenhouse facilities should be adjusted accordingly.

For crops with high requirements for growth temperature, such as solanaceous plants (eggplants, peppers, tomatoes, etc.) and melon crops, it is necessary to use a greenhouse with double-structured four-layer film covering during the cold winter months. Otherwise, they are prone to cold damage, resulting in slow growth and difficulty in harvesting.

2. The winter greenhouse utilizes a ventilation method of "late ventilation and early coverage" for its greenhouse.

During the winter (before January), greenhouses should be kept closed for extended periods, with the indoor temperature not exceeding 30°C. To regulate the greenhouse temperature, intermittent ventilation should be maintained. The greenhouse should remain closed for no more than 5 days, and ventilation operations should be conducted every 5 days to address harmful gases inside, which can affect the normal growth of crops.

During winter, due to the cold weather, ventilation should be scheduled on sunny days. Ventilation should be carried out at the lower exhaust outlets. If there is no wind, you can also choose to ventilate through the upper air outlets of a film greenhouse to accelerate the release of harmful gases. The ventilation period typically starts at 9:00 AM, with the initial opening of the small tunnels inside the greenhouse at 10:30 to 11:00 AM. Close the small tunnels before 2:00 PM to maintain the normal temperature and promote plant growth.

3. Managing film greenhouses is a task that cannot be overlooked. If there are gaps in the greenhouse during winter, the crops may freeze to death. Therefore, vegetable farmers need to control the wind leakage and heat dissipation in the greenhouse, ensuring that the greenhouse film interface is tightly sealed and covers the soil.

4. Scientific vegetable farmers know that each crop has different frost resistance, which is mainly related to the concentration of cells within the plants. Therefore, it should be noted that nitrogen fertilizer should not be applied locally, as this will lead to excessive growth and soft growth in plants, thereby reducing their frost resistance. One way to enhance the frost resistance of crops is by controlling their excessive growth.

During the winter season in film greenhouse vegetable cultivation, as long as vegetable farmers adhere to the above points, there will be no major issues with temperature management.