Solving measures for abnormal seedlings of watermelon and muskmelon in spring

The main results are as follows: 1. The uneven emergence of seedlings is mainly caused by the uneven ground temperature and humidity of the seedling bed. When laying a ground hot line, the wiring spacing at the front of the greenhouse is 3-4 cm, and the wiring spacing along the rear of the greenhouse is 7-8 cm, so as to make the bed temperature uniform; when large and small seedlings appear, move the big seedlings to the lower temperature at the front of the greenhouse to make the seedlings grow uniformly; when the humidity is uneven, the seedlings emerge better on both sides, and seedlings are easy to be lacking in the middle of the bed, and mulch should be covered after sowing to keep the surface humidity uniform. Uneven thickness of soil cover will also cause uneven emergence of seedlings, so cover the soil evenly. 2. The unearthed with shell is caused by insufficient bottom water and thin covering soil. The main measures must be fully watered, covering the soil thickness of 1.5 cm is appropriate; if the seed shell is found unearthed, in the morning when the seedbed is wet, gently remove the melon shell by hand. 3. The main causes of overgrown seedlings are high humidity of seedling bed, high temperature (especially high night temperature), large amount of available nitrogen fertilizer, lack of light or small spacing between melon seedlings. To prevent the excessive growth of melon seedlings, it is necessary to prepare nutritious soil according to the requirements, strengthen the temperature and humidity management of the seedling bed, ensure that the night temperature after emergence is not higher than 15 ℃, reasonably water, strengthen ventilation, reduce humidity, enhance the light of the seedling bed, and increase the seedling distance. 4. The ossified seedlings showed small leaves, dark color, thin stems, short nodes, slow growth, small roots and so on. It is mainly caused by long-term low seedbed temperature, long-term dry seedbed, insufficient fertilization, lack of nitrogen fertilizer, excessive fertilization and so on. To prevent ossified seedlings, we should use nutritious soil to raise seedlings, avoid undernutrition and root burning, maintain suitable temperature and humidity of seedling bed, and appropriately refine seedlings according to seedling conditions and weather conditions. 5. The absence of growth point of melon seedlings is caused by old seeds or fertilizer damage or drug damage. For the watermelon seeds stored for more than 3 years, there are many watermelon seedlings without growth point, and the newly unearthed melon seedlings have relatively young growth point and weak resistance to fertilizer and drugs. if the concentration of foliar spraying or topdressing is on the high side and the spraying amount is high, it is easy to destroy the growth point.