Spring-planted watermelon flowering and fruit setting are affected by weather, how should melon farmers respond?

This year the temperature in early spring was relatively low, and there was a late spring cold spell. In some areas there were many cloudy days and relatively little sunlight. These factors all affect the flowering and fruit setting of spring-planted watermelon. So when encountering this situation, how should melon farmers respond? In response to these issues, preparations must be made in advance!

◆ Watermelon seedlings are thin and weak

Although watermelon seedlings are all raised in nutrient pots, the seedling root system is fine and weak, with poor fertilizer absorption capacity. In addition, high temperature and high humidity can easily lead to yellow and weak seedlings, affecting recovery after transplanting.

Suggestion: During the seedling stage, a foliar fertilizer containing phosphorus, potassium and calcium can be sprayed to promote more roots and strong seedlings.

◆ How to balance excessive vegetative growth and stiff seedlings after planting?

Stiff seedlings appearing after watermelon seedlings are transplanted are mainly caused by root damage during transplanting, low soil temperature, clayey soil and high moisture, which lead to slow root growth and few new white roots, and further cause slow recovery, no seedling growth and stiff seedlings. Stiff seedlings are a major physiological obstacle in the watermelon seedling stage.

Suggestion: For this situation, in addition to choosing loose and breathable soil for planting, strengthening drainage and watering appropriately, it is more important to supplement phosphorus and calcium to promote roots. Supplementing phosphorus promotes main root development, and supplementing calcium promotes white root growth. With a well-developed root system, fertilizer absorption capacity is strong and seedling vigor is robust.

Vigorous excessive vegetative growth after watermelon seedlings are transplanted is mainly caused by insufficient light, excessively high temperature and improper fertilizer and water management. In particular, applying too much base fertilizer and excessive nitrogen-containing chemical fertilizer with insufficient phosphorus, potassium and calcium leads to overly rapid stem and leaf growth, affecting fruit setting and increasing the rate of plants without fruit.

Suggestion: Reasonably regulate temperature, humidity and light. Manage seedbed temperature in stages, ventilate in a timely manner, reduce humidity, increase light and avoid excessively high temperature; lower night temperature and increase the day-night temperature difference; under insufficient light conditions, appropriately lower temperature and humidity. During the vine extension stage, reduce the application of nitrogen-containing chemical fertilizer and focus on supplementing phosphorus, potassium and calcium nutrition.

◆ Few flowers and low fruit setting rate, is it due to improper flower promotion work?

There are many factors affecting watermelon flowering and fruit setting. Excessive planting density, low temperature and rainy days during the flowering period, or high temperature and drought can all lead to poor pollination and fertilization and thus a low fruit setting rate. In addition, fertilizer and water management is even more critical. Applying too much nitrogen fertilizer before flowering makes vegetative growth excessive and intensifies flower drop; a lack of reproductive elements such as boron and zinc during the flower bud differentiation stage results in few flowers, weak flowers and many deformed flowers, and a low fruit setting rate.

Suggestion: When fixing vines and pruning, pay attention to ventilation inside the greenhouse, and at the same time spray a foliar fertilizer containing trace elements such as boron and zinc to promote large flowers and thick stems, significantly increase the fruit setting rate, and make young fruit develop evenly.

[Warm reminder]

For spring melon seedlings, promoting roots and strong seedlings in the early stage is very critical. Robust plants have good resistance to temperature and diseases. Therefore, it is suggested that melon farmers can supplement phosphorus before and after transplanting melon seedlings to promote main root development, and supplement calcium to promote white root growth. With a well-developed root system, fertilizer absorption capacity is strong and seedling vigor is robust. Before flowering, elements such as boron and zinc can be supplemented to store nutrients for the flowering period, which can effectively increase the fruit setting rate.