April is the development period of watermelon fruit in the greenhouse, coinciding with the alternating cold and warm weather, easy to crack melon, to do a good job in the temperature control of the shed, to avoid temperature fluctuations caused by cracked melon.
Temperature control in the shed
Before the female flowers come out, ventilation should be strengthened, especially at night, and the temperature above 15 degrees Celsius should be opened for ventilation to promote more female flowers. Within 7 days after flowering, it is necessary to do a good job of heat preservation and control the temperature in the shed between 18 degrees Celsius ~ 35 degrees Celsius to promote the development of young fruits and reduce deformed fruits. The temperature in the shed is controlled between 15 degrees Celsius ~ 30 degrees Celsius during the fruit expansion period, and the inner membrane should be covered before encountering strong cooling. After low temperature, spray 600 times of Livi Youguo + 2000 times of Livpeng to strengthen foliar nutrition supplement and prevent physiological yellowness caused by abnormal temperature.
Fertilizer and water control
Ventilation and vine control in the early stage, water control and calcium supplementation from before flowering to fruit setting period, neat melon sitting, less deformed melon and cracked melon, and high fruit setting rate. Before sitting on the melon or after sitting on the melon, the first top dressing should be thin fertilizer and thin water, and this period of water control and calcium supplementation will help reduce the cracking of young fruits.
Nitrogen control at the fruit expansion stage, calcium, potassium, magnesium trace elements and small molecule organic matter are supplemented to improve yield and quality. Within 15~25 days after fruit set, sufficient fruit fertilizer should be applied, and fertilizer water should be controlled or stopped after 25 days of fruit set. It is recommended to use 2 kg ~ 3 kg of Mill extract bulking fruit fertilizer + 1 kg of Liwei energy + 15 kg ~ 25 kg of Dedefu compound fertilizer for 1 time ~ 2 times, with an interval of 5 days ~ 7 days, with an appropriate amount of water, generally 7 minutes ~ 10 minutes per mu of drip irrigation.
Pest and disease control
Sclerotinia sclerotinia and gray mold prevention and control temperature 18 degrees Celsius ~ 23 degrees Celsius, rainy, poor ventilation and light transmission, high humidity, more nitrogen, vigorous growth and easy disease. Especially in greenhouses with a lot of dripping, sclerotinia and gray mold are severely affected. For prevention, use 50% Ruizhen 1000 times + Liweijian 800 times + Jinyiwei 1000 times, and at the same time strengthen ventilation and reduce humidity. Note that the control of gray mold must start before the flowering period, otherwise it will be difficult to control the fruit-bearing stage.
The vine blight control and extension period is affected by the large temperature difference between day and night, which is easy to cause cracked vines to be infected with vine blight. Therefore, the prevention and control of vine blight should first reduce the cracked vine, and the key to prevention and control is early prevention. The specific scheme is as follows: calcium supplementation increases the toughness of the vine, reduces the cracked vine, only calcium is supplemented when the ground is dry after 4~6 nodes during the vine extension period, and 2 kg of drip irrigation per mu is used with Liweixin, and the water is appropriate. Luna run 2000 times or sharp harvest 1500 times or 1500 times of isareare + 800 times of Liweijian + 1000 times of Jinyiwei for vine blight control.
Bacterial disease control In April, when the humidity is high during the vine extension period, bacterial diseases often occur severely. The key to the prevention and control of the disease is to strengthen ventilation and reduce the humidity in the shed, and the prevention and control agents can be selected: Lizhan 1000 times + Liweijian 800 times + Jinyiwei 1000 times spray, pay attention to the use of dew after drying, and close the shed only after the liquid medicine is dry.
Yellow aphid control yellow aphid force 2000 times or 50% pymetrozine water dispersible granules 2000 times + Anrongle 5000 times, fine spray on the back of the leaf.
The management measures of greenhouse watermelons in April are introduced here, and I hope it will be helpful to everyone. If you want to buy high-quality and high-yield vegetable seeds, you can download the seed bank App, and the country's excellent vegetable varieties are available for everyone to choose.
Download the Torrent App