Latest Causes of Low Fruit Setting Rate in Greenhouse Melons and Control Measures
Through greenhouse cultivation of melons, artificially regulating temperature and humidity can significantly increase melon yield, but if management is improper, it will instead cause a decrease in the fruit setting rate of melons. This not only affects the yield and quality of melons, but also delays the time for melons to reach the market, reducing returns. So what are the causes of low fruit setting rate in greenhouses? Let's take a look together with the editor,
I. Causes of Low Fruit Setting Rate in Greenhouses
1. Low temperature and insufficient light
After melons are planted in spring, the temperature in some areas changes unpredictably, and late spring cold spells may even occur, or there may be continuous rainy days. If insulation is improper, it will restrict the growth and development of melons and affect flowering and fruit setting. When light is insufficient, it will force the internodes and petioles of melons to elongate, cause poor flower bud differentiation, reduce the accumulation of nutrients in the fruit, lower the sugar content, and worsen the quality.
2. Excessive humidity
At low temperatures, if the greenhouse is not ventilated for a long time, it will lead to high air humidity and relatively saturated soil moisture. This not only affects the root absorption capacity and leaf transpiration, but also makes it difficult for pollen to disperse or causes pollen rupture, hindering fertilization, affecting pollination results, and leading to flower and fruit drop.
3. Improper fertilization
Applying too much base fertilizer and too little topdressing, especially excessive nitrogen fertilizer causing excessive vegetative growth, will restrict flower bud differentiation. Using too little organic fertilizer, or even no organic fertilizer at all, is also unfavorable for flower bud differentiation.
4. Severe pests and diseases
Pests and diseases will seriously hinder the cultivation of strong seedlings, thus affecting the stress resistance of the plants, and flower and fruit drop is very likely to occur in the later stage.
II. Control Measures
1. Suitable temperature and humidity management
During the fruit setting period of melons, the daytime temperature should be maintained at around 28-30 degrees. If it is lower than 18 degrees or higher than 32 degrees, it is unfavorable for pollination and fruit setting, and deformed melons are very likely to form. At night, it is suitable to maintain 15-18 degrees. In protected cultivation, temperature management should be strengthened. In spring, the temperature rises quickly, so the early growth stage should focus on increasing temperature, and after flowering and fruit setting, attention should be paid to lowering the temperature. When different temperatures exceed 32 degrees, a shade net should be covered on the greenhouse film to provide appropriate shading and cooling.
2. Improve light conditions
On sunny days, uncover the plastic film, uncover early and cover late, to extend the lighting time, which both supplements light and preserves heat. On rainy days, promptly uncover the film at both ends of the greenhouse or at the base of the greenhouse to increase scattered light. You can also choose drip-free film to improve light conditions, and you can choose films such as polyethylene and vinyl acetate. Their light transmittance is high and can increase light intensity by about 25%.
3. Reasonable fertilization
The flowering and fruit setting period of melons is the transition period from vegetative growth to reproductive growth. At this time, compound fertilizer should be applied in a timely manner or foliar fertilizer should be sprayed. It is not suitable to apply only nitrogen fertilizer. This promotes the distribution of nutrients to the young melons and enhances plant vigor, while also preventing excessive vine growth. When the plants show excessive vegetative growth, spraying paclobutrazol or using the method of lowering the growing tip and tying the vines can significantly inhibit stem and leaf growth and promote fruit expansion.
4. Pest and disease control
Common melon diseases include fusarium wilt, phytophthora blight, and powdery mildew. The main pests are aphids, whiteflies, and others. Focus on controlling powdery mildew, viral diseases, and aphids. Control should be integrated, with prevention as the main approach. When pests and diseases are found, promptly use pesticides in combination. At the same time, pay attention to greenhouse ventilation, control suitable temperature and humidity, and promptly train vines, tie vines, and remove weeds to improve the plant's resistance to pests and diseases.
The above is an introduction to the causes of low fruit setting rate in greenhouse melons and control measures. We hope it can help you. To learn more related knowledge, please keep following us.