The application of phosphorus, potassium, calcium, and magnesium fertilizers during the expansion of watermelons and melons can prevent cracking of melons, increase sweetness, and promote coloration. In the early, middle, and late stages of watermelon and melon enlargement, each leaf is sprayed once with 800-100 times Star Phosphorus No. 1, Starfish calcium and magnesium No. 1 mixture, or 0.1% magnesium sulfate, 0.2% calcium nitrate, and 0.3% phosphoric acid. Dihydrogen potassium mixture, uniformly wet all stems and leaves, to start dropping drops of water is appropriate. In addition, in the early stages of the expansion of watermelon and melon, it is also necessary to apply 600-800 times the amount of phosphorus and potassium in the roots, and Xingfen calcium and magnesium mixed liquid in the initial stage of the expansion of the watermelon and melon. Each of the plants is dripping 0.5-1 kg, evenly poured in the watermelon and melon. In the soil around the root of the plant, it is appropriate to completely penetrate the soil without flowing through the soil. Zhejiang ocean family co.,ltd , https://www.ocean-family.com