How to Plant and Manage Watermelon in a Greenhouse? Latest Technical Method Tutorial
Watermelon used to be a summer fruit, but now it is all grown in greenhouses. Greenhouse cultivation artificially provides a small microclimate with heat and moisture retention and adjustable temperature, which can be isolated from the outside climate and used for off-season planting, so that growing watermelon is no longer limited by the season. However, the environment inside the greenhouse must all be controlled by yourself, and it loses the role of natural regulation, so everything must be done carefully and meticulously. To manage the greenhouse environment yourself, you need to pay attention to the following aspects.
1. Temperature
Watermelon likes high temperatures and strong light, and grows well in such an environment; photosynthesis proceeds fully, the growth quality is also better, and the yield increases. Generally, the temperature inside the greenhouse is also affected to some extent by the outside. When the temperature outside the greenhouse is high, the temperature inside the greenhouse will rise accordingly, and when the temperature is low, it will also drop, but overall it will be somewhat higher than the outside temperature. Therefore, when the temperature difference between day and night is large, the daytime temperature will be higher than outside, and at night the temperature will drop, so the skylights must be opened during the day for ventilation and cooling. At night, straw mats are added on the outside to increase the temperature.
2. Humidity
When the temperature inside the greenhouse rises, the transpiration of watermelon accelerates, and the water produced will condense on the greenhouse film and finally drip down. Dripping onto the soil will increase soil humidity, or dripping onto the leaves can easily cause disease, and then transpiration occurs again, forming a vicious cycle. Therefore, generally after irrigation, when the temperature rises, the side doors are opened for ventilation to reduce humidity. Do not water on cloudy and rainy days, and water less on very sunny days, to avoid excessive humidity that cannot evaporate. Generally, ventilation is done at night and closed in the morning. You can also manually scrape off the water droplets when they form on the greenhouse film. In addition, appropriately raising the temperature can reduce humidity.
3. Light
Watermelon likes light, and sufficient light is needed to satisfy its growth. Generally, the light transmittance of the watermelon mulch film directly affects the light received. For example, if some films are more transparent, the light will be good; if the film has poor light transmittance, its ability to receive light will also decrease. Therefore, generally a single-layer film has better light absorption, while a double-layer film reduces received light by about 40%. In addition, when setting up the greenhouse, cement frames will block sunlight more than other frames. The construction site and orientation of the greenhouse directly affect light.
4. Air
The inside of the greenhouse is a relatively closed environment, and the air must circulate in a timely manner to ensure that toxic substances do not accumulate inside the greenhouse. The main thing is to manage the oxygen and carbon dioxide content. Generally, watermelon growth requires a large amount of oxygen, while at night watermelon releases some carbon dioxide. When oxygen is insufficient, the windows need to be opened in time for air exchange. During the day, carbon dioxide is consumed for growth, so carbon dioxide needs to be supplemented. Generally, you can use a plastic container to hold some water, then add sulfuric acid equal to one third of the water volume. Place it in various places inside the greenhouse to supplement carbon dioxide.
The work to be done in greenhouse watermelon cultivation is very different from open-field cultivation. In greenhouse cultivation, temperature and humidity are the key management targets, while in open-field cultivation, fertilizer and water are the key management matters. Therefore, when growing watermelon in a greenhouse, you must pay attention and do a good job in these aspects of management.