Greenhouse vegetable planting: pay attention to humidity control

Now that outside temperatures are dropping, greenhouse ventilation is reduced, humidity inside the greenhouse rises, and diseases increase, especially bacterial diseases, which occur frequently. Here, vegetable growers are reminded to adjust farming operations in time according to weather changes and to take good humidity control measures. Humidity control can be carried out in the following four aspects:

1. Reasonable ventilation to reduce humidity. Ventilation is the main means of regulating temperature and humidity inside the greenhouse. In the current season, temperatures are gradually decreasing and ventilation is reduced. To lower humidity, vegetable growers are advised to ventilate in stages: when the temperature is low, open the vent a little for air exchange, and gradually open it wider as the temperature rises. If the greenhouse has good insulation performance, vegetable growers can also ventilate appropriately at night to ensure a suitable environment inside the greenhouse.

2. Combine plastic film with straw to reduce water evaporation. That is, lay plastic film along the planting rows to reduce soil water evaporation, especially after watering, when the effect is even more obvious. At the same time, laying straw along the operation rows can play a regulating role: when humidity is high at night, the straw can absorb some moisture, and during the day when humidity is low, the straw can release the moisture it stores, which can help regulate air humidity. The straw can also prevent the ground surface from being trampled hard during manual operations.

3. Improve irrigation techniques. The traditional method of flood irrigation not only wastes water but also easily causes root rot, increasing humidity inside the greenhouse and triggering diseases. New irrigation techniques such as drip irrigation and sprinkler irrigation allow water to gradually infiltrate the soil and improve water use efficiency. At the same time, on the day of watering and the next day, increase ventilation as the temperature rises to remove moisture as quickly as possible.

4. Change the method of pesticide application. At present, vegetable growers still mainly use spraying for pesticide application, which will inevitably increase humidity inside the greenhouse. Vegetable growers are advised, when spraying on sunny days, to do so preferably around 3 p.m. and to finish spraying before dark as much as possible to ensure the pesticide solution is fully absorbed. During consecutive cloudy days, vegetable growers can choose fully automatic sprayers and mist sprayers and reduce the amount of pesticide used. In addition, for pesticides used on the roots, it is best to use root drenching, which ensures efficacy while reducing soil humidity.

Li Bingcai