What if the zucchini in the greenhouse only blossoms but doesn't bear fruit?

This is mainly caused by physiological obstacles: first, the partial application of nitrogen fertilizer in the base fertilizer promotes the excessive growth of zucchini, the increase of leaf area and serious shade. Second, the temperature in the greenhouse is too low or too high. Third, there is insufficient moisture or too much humidity in the greenhouse. Such an environment will greatly inhibit the vitality of pollen and style. For this reason, the following four measures should be taken for prevention and control. Improve the conditions of drainage and irrigation in the shed so that open water can drain and dark water can seep away. When beginning to bear melons, if you encounter a continuous drought of about 10 days, then carry out furrow irrigation, but you must prevent flooding. The additional application of phosphorus and potassium fertilizer is generally sprayed with 0.2% potassium dihydrogen phosphate solution every 5 murals every 7 days. Artificial pollination is carried out at 9: 00 am every morning when the male flower blooms at its peak. Pick the male flower, remove its Corolla, and gently apply the anther on the stigma of the pistil. One male flower can give 3 female flowers. Hormone treatment one is available 20murmur30mg / L 2mae4murD in the morning of flowering, with a brush dipped in liquid on the pedicel or stigma, ovary, but to prevent the liquid from splashing on the stems and leaves. Second, it can be sprayed on the stigma of female flowers with 40Mel 50mg / L tomato spirit. The third is to remove the old leaves and the residual flowers. The basal foot leaves should be removed properly, and at the same time, too many female flowers and redundant male flowers should be taken care of.