What problems should be paid attention to in watermelon seedling management?

What problems should be paid attention to in watermelon seedling management? (1) temperature management: in temperature management, two tendencies should be avoided, one is that they do not dare to uncover the film ventilation for fear that the seedlings will be frozen, resulting in high temperature and humidity in the seedling bed and causing the seedlings to grow excessively, and the other is that the ventilation rate is too large, which makes the temperature in the bed too low, resulting in slow growth of seedlings and affecting the development process. The problem that should be paid attention to in temperature management is that the night temperature should be kept low, generally no more than 15 ℃, in order to facilitate the differentiation of female flowers. (2) Water management: pay attention to not too much humidity on the bed in the early stage. If the humidity is too high, coupled with low temperature, it is easy to appear seedling "retting root" phenomenon and induce the occurrence of quenching disease. The soil relative temperature required at the seedling stage is about 80%, and the air relative humidity is 50% and 60%. Generally speaking, as long as the bottom water is watered thoroughly when sowing, there is no need to water in the early stage of seedling cultivation. If the soil surface of the seedbed turns white at noon, it means that there is a shortage of water and should be sprinkled at noon. Note that the water should be sprinkled thoroughly without getting too wet. After sprinkling water, dry the water droplets on the leaf surface, and then cover the film, otherwise it is easy to cause the disease because of excessive humidity. (3) Light management: pay attention to make the seedbed receive as much light as possible. If the light is not enough, the stems and leaves of the seedlings are thin, easy to grow, the root growth is poor, the seedlings are slow after transplanting, and the growth period is delayed. The main measure to increase light is to uncover the opaque cover in time; keep the film clean; even on rainy days, as long as the temperature in the bed is not too low, the cover should be opened to increase the penetration of scattered light. (4) Disease and pest control: we should pay attention to strengthening the prevention and control of diseases and pests. The main diseases in seedling stage are quenching disease, sometimes wilt disease, and the main pests in seedling stage are mole goo, aphids and so on. (5) Seedling exercise: attention should be paid to seedling training before planting. By refining seedlings, the adaptability and stress resistance of seedlings can be enhanced, and the seedlings will slow down soon after planting.