What kind of fertilizer is best for growing watermelons?
What kind of fertilizer should be used for growing watermelons? Watermelons are heavy feeders, and their requirements for fertilizer type and quantity vary at different growth stages. Growers should pay attention to combining organic and chemical fertilizers appropriately, while carefully managing the application rates of nitrogen, phosphorus, and potassium. Adequate base fertilizer is essential for ensuring high watermelon yields. Throughout the plant's life cycle, base fertilizer accounts for about 60% of the total nutrient supply needed.
When applying base fertilizer, prioritize organic fertilizers and phosphorus fertilizers that are long-lasting and nutrient-complete, while controlling the use of quick-acting nitrogen fertilizers to prevent excessive vegetative growth due to high nitrogen levels during the seedling stage. If sufficient base fertilizer has been applied, no additional seedling fertilizer may be needed; however, for plots with insufficient base fertilizer or where its effect is not evident, timely application of seedling fertilizer can promote strong root development and healthy seedling growth.
When the seedlings have 2-3 true leaves, the first top-dressing should be carried out. The main fertilizer should be quick-release nitrogen fertilizer. According to the standard of applying 2-3 kilograms of urea per mu, it should be applied in the form of hole-dressing at a distance of 10 centimeters from the seedlings. After the watermelon vines start to stretch, during the period when the vines are growing and flowers are forming, the demand for nitrogen, phosphorus and potassium is very high. At this time, the second top-dressing should be carried out.
When applying additional vine-growing fertilizer, priority should be given to fertilizers that are rich in nutrients, have a large quantity, and have a long-lasting effect, such as compost or compound fertilizers. For each acre, 15 kilograms of compound fertilizer can be applied. At the same time, make holes about 10 centimeters away from the plant's rootstock and apply the fertilizer. Use a shovel to mix the soil and the fertilizer together, then cover the hole, tamp it down, level the ground, and finally, give it an appropriate amount of water to promote absorption.
The fruit expansion period of watermelons is a crucial time for fertilization. If there is a lack of nutrients or if the supply is not timely, problems such as small-sized watermelons and poor taste may occur. Generally, the third application of fertilizer is carried out during this period, and it is usually implemented in two steps.
When the young fruits reach the size of an egg, the first top-dressing should be carried out at the appropriate time. A ditch can be dug 30-40 centimeters away from the plant on one side. Apply 15-20 kilograms of superphosphate and 6-7 kilograms of potassium sulfate per mu. If there is readily available wood ash available, it can be used instead of potassium sulfate, as wood ash is rich in potassium and phosphorus, providing both nutrients and being environmentally friendly.
When the fruit reaches the size of a bowl, apply the second melon enlargement fertilizer at the right time. You can spray a 0.2% potassium dihydrogen phosphate foliar fertilizer every 7 days for 2-3 times in succession.
After the first batch of melons is harvested, the fourth fertilization should be carried out immediately. It is necessary to apply an efficient phosphorus and potassium dual compound fertilizer. Each acre can be fertilized with 10-15 kilograms of potassium dihydrogen phosphate foliar fertilizer to quickly replenish phosphorus and potassium elements for the plants, promoting growth and flower bud differentiation, increasing the number of flower buds on the plants, and preventing premature leaf and vine senescence. In the normal growth of watermelons, in addition to the necessary nitrogen, phosphorus, and potassium nutrients, there are also special requirements for trace elements such as calcium and magnesium.
