Many vegetable seedlings are not cultivated by professionals, and diseases such as root rot and verticillium wilt will inevitably occur. The seedling stage is generally about 40 days. Because the temperature at seedling stage is unstable, we can look at the quality of seedlings, choose strong seedlings, and eliminate weak seedlings after sufficient watering, which can improve the survival rate. The resistance and disease resistance of small seedlings and weak seedlings are poor, and it is difficult to support the slow growth period, but the strong seedlings can.