How to manage watermelon in greenhouse when it rains continuously in spring?

Due to insufficient light, melon seedlings have weak photosynthesis, malnutrition, slow growth, pale leaves and cotyledons falling off, which are prone to stiff seedlings and sudden lodging, resulting in a large number of dead seedlings. Management measures: clear the grass in the morning, clean the dust on the film, pat off the small water droplets on the film, maintain good transparency, cover the grass at night to keep warm, and apply pesticides to prevent diseases if necessary.

It's raining all the time.

The humidity in the seedbed is high, the light is poor, the temperature is low, the photosynthesis is weakened, and the nutrient accumulation is small, but the respiratory consumption is not reduced, the seedlings are yellow, and the disease is aggravated. Management measures: As long as it doesn't rain, the cover must be uncovered during the day to increase the scattered light and avoid leaving the cover uncovered for several days. The surface of the frame can be paved with 1 ~ 1.5cm thick dry fine soil or plant ash, and watering and spraying should be stopped at the frame. Properly ventilate on the leeward side at noon.

3. foggy days

Poor light intensity and high air humidity make the leaves of melon seedlings easy to accumulate water, and easy to be infected with anthracnose and damping-off disease. Therefore, in foggy days, it is necessary not only to seal the seedbed to prevent the fog from entering, but also to remove the cover in time and properly ventilate and transmit light after the fog completely dissipates.

It was cloudy and sunny for a long time.

The bed temperature rises sharply, and the seedlings lose too much water, which leads to physiological water imbalance, wilting, growth stagnation and even death. Management measures: let the seedlings gradually see the light and uncover it in the morning, so that the seedlings can see more light at a lower temperature, thus having a longer adaptation process to strong light. When the temperature rises to a certain extent, straw can be covered on the seedbed for shading, or warm water of 10℃ ~ 20℃ can be sprayed to supplement water loss and relieve wilting. You can also ventilate as soon as possible before the storm comes to reduce the temperature of the seedbed.

5. Strong winds and cold currents

Uncover the straw mulch as usual every day, so that the seedlings can have a certain time to see the light, but it should be uncovered later and earlier, usually after 1 1 and before 2 pm, and the specific time is not short. At night, heat preservation measures should be strengthened according to weather conditions.

Cucumber seedlings lose too much water, which leads to wilting, growth stagnation and even death. Management measures: let the seedlings gradually see the light and uncover it in the morning, so that the seedlings can see more light at a lower temperature, thus having a longer adaptation process to strong light. When the temperature rises to a certain extent, straw can be covered on the seedbed for shading, or warm water of 10℃ ~ 20℃ can be sprayed to supplement water loss and relieve wilting. You can also ventilate as soon as possible before the storm comes to reduce the temperature of the seedbed.