What to Do About Stunted Watermelons in Spring? Cause Analysis and Control Measures
1. Over-vigorous vine growth: the nutrients produced are mostly consumed by stem and leaf growth and cannot meet the needs of fruit enlargement, resulting in a rampant growth state. Strong seedlings should be raised to lay a good foundation for normal fruit development. Before and after fruit set, the amount and timing of the fruit-swelling fertilizer should be adjusted according to the size of new leaves, the thickness of the vines, the length of the internodes, and the length from the vine tip to the node of the opened female flower...
The causes of stunted watermelons fall into the following categories: 1. Over-vigorous vine growth: the nutrients produced are mostly consumed by stem and leaf growth and cannot meet the needs of fruit enlargement, resulting in a rampant growth state. Strong seedlings should be raised to lay a good foundation for normal fruit development. Before and after fruit set, the amount and timing of the fruit-swelling fertilizer should be adjusted according to the size of new leaves, the thickness of the vines, the length of the internodes, and the length from the vine tip to the node of the opened female flower. If the length from the vine tip to the node of the opened female flower exceeds 67 cm, it indicates that the vine is growing too vigorously and its growth should be suppressed; if the length is less than 50 cm, it indicates that the vine is growing weakly and should be topdressed immediately to promote growth; if the length is within the range of 50-67 cm, it indicates that the vine is growing normally.
2. Dry soil and insufficient fertilizer and water: if fertilizer and water are insufficient during the fruit enlargement period, stunted fruit is easily formed. Therefore, the watermelon field should be irrigated, with the amount of water increasing from small to large, and the water should not cover the bed surface. The water should not remain in the field for too long, and irrigation should be done in the evening or at night to avoid burning the roots at high temperatures. When developing watermelons in hilly areas, water storage should be increased before winter, and the method of raising seedlings and transplanting should be adopted to achieve early fruit set and reduce the impact of drought on fruit enlargement. When the young fruit grows to the size of an egg, topdress with fruit-swelling fertilizer in a timely manner.
3. Insufficient functional leaves: generally speaking, fruits with more leaves grow larger and are of better quality, so cultivation should include a considerable number of functional leaves for photosynthesis to meet the needs of fruit enlargement.
4. During pollination, the amount of pollen from male flowers applied to the stigma of female flowers is insufficient. The number of seeds has an important influence on fruit development. Under the same conditions, fruits with more seeds grow larger. Therefore, the best timing should be chosen to apply as much pollen with strong viability as possible to the stigma, so as to increase the number of seeds and achieve the goal of high yield.
5. Female flowers that are slender, weak, and have sparse downy hairs are not easy to set fruit after pollination, and even if fruit is set, it is difficult for it to grow large. Therefore, female flowers with well-developed buds, large size, and vigorous growth should be selected for pollination. The main characteristics of high-quality female flowers are a thick fruit stalk, a large ovary, normal shape, a tender green and glossy color, and dense downy hairs.
6. Leaves severely damaged by diseases and pests cannot carry out photosynthesis normally, affecting fruit development.
7. If fruit set is too close or too far, fruit enlargement is affected in many ways and the fruit becomes stunted.