Continuous rainy weather can have a very negative impact on greenhouse vegetable production. The humidity in the shed is too high, which is conducive to the occurrence and spread of various diseases; the light is weakened, the temperature is reduced, and the growth of vegetables is inhibited. Therefore, in the late autumn and winter and spring, the focus of shed management should be shifted to temperature and humidity management.

First, reduce humidity and suppress diseases

The temperature inside the facility is relatively high after the shed is sewn, and at the same time, a high-humidity environment is easily formed. The high temperature and high humidity create favorable conditions for the occurrence and spread of the disease. During production, the following measures can be taken to reduce the humidity in the shed. Of course, the combination works better.

1. Cover with no dripping film

Due to the temperature difference between the inside and outside of the shed, dew condensation on the shed film is inevitable. The dew on the surface of the ordinary plastic film is evenly distributed, so the drip surface is large and the air humidity is increased. After the drip-free film is used, although the surface is dew condensation, water droplets flow down the film surface, the drip surface is small, the humidity is significantly reduced, and the light transmission performance is good, which is conducive to increasing temperature and reducing humidity.

2. Cover the mulch

Covering with plastic film can reduce the evaporation of soil moisture and reduce the frequency of irrigation, which is an important measure to reduce the humidity of the air in the shed. For example, in the shed, double ridges with different ridges and small ridges are used to cover the ridges under the mulch when watering. The mulch film prevents the evaporation of water, which prevents the air humidity in the shed from increasing significantly after watering.

3. Reasonable dense planting

The planting density in the shed should not be too dense to facilitate ventilation and reduce air humidity.

4.Ventilation

Ventilation is the main measure for dehumidification. Generally, it should be carried out when the temperature is high around noon. The top and waist winds are the main ones. If the humidity in the shed is high, and the air temperature is above the lower limit of crop growth, gradually increase the ventilation and try to reduce the air humidity as soon as possible, but the cooling caused by ventilation should be based on the premise that no cold damage occurs to the crop.

5. Reasonable watering

Watering is the main factor leading to the increase of humidity in the shed. The number of watering and the amount of watering each time depends on the weather, soil conditions, vegetable types, growing season and growth potential. Generally, small water or ditch watering should be used, and large water should not be flooded. The water for planting and slow-growing of fruits and vegetables should be thoroughly irrigated, and sufficient water should be supplied during the fruiting period, and watering is generally not required for other periods. When the temperature in the shed is low, especially when air cannot be ventilated, watering should be controlled as much as possible. Generally, it can be watered on a sunny day from 10 to 12 in the morning with ventilation and moisture removal. When conditions permit, sub-film furrow irrigation or drip irrigation can be used to reduce the amount of irrigation and evaporation.

6. Strengthening cting loose soil

After planting, before mulching, and tilling the soil in time after watering, it can reduce evaporation, maintain soil moisture, reduce watering times, and reduce air humidity.

7. Heating and dehumidification

For every 1 ° C increase in the indoor temperature of the shed, the relative humidity in the air decreases by 3% to 5%. Adopting the method of heating and dehumidifying can not only meet the temperature needs of vegetables, but also reduce the relative humidity of the air. When the plant has passed the seedling stage and the resistance is slightly stronger, the temperature of the watering canopy should be raised to about 30 ° C for 1 hour, and then ventilated and dehumidified. It can be repeated once when the shed temperature is lower than 25 ° C after 3 to 4 hours.

8. Change medication

Vegetable farmers use spray as the main medicine, which will inevitably increase the humidity in the shed. It is recommended that when spraying on a sunny day, it is best to be carried out around three in the afternoon, and try to spray it before dark to ensure that the liquid is completely absorbed. On cloudy days, vegetable farmers can use automatic sprayers and mist sprayers to reduce the amount of medication. If conditions permit, it is best to use the dust method and the smoke method to avoid the increase of air humidity in the shed and improve the control effect.

9. Reduce ineffective transpiration

In the middle and late stages of greenhouse vegetable production, plant transpiration is the main source of indoor water vapor. Agronomic measures such as trimming branches, topping and topping, removing dead leaves, and removing weak plants must be timely to improve the plant population structure and reduce plant inefficiency Transpiration.

Zhengzhou Delong Chemical CO., Ltd. is the production base of plant growth regulators in China, which established in 2009, specializing in offering plant protection products. If you have any question, contact us any time.