The growth of watermelon is not very good. The melon seedlings grow very slowly. They have been planted for almost two months. The melon seedlings are relatively short and there are not many vines. There are only a few leaves on the plant. The leaves have many holes, are incomplete, and even have some yellow spots, and the edges are curled. This is the disease of watermelon seedlings.

Some melon farmers, in order to sell watermelons in advance and sell them at a good price, plant them earlier in spring. When planting outdoors, the growth of melon seedlings is very vulnerable to weather damage. The temperature in spring is generally unstable, and there will be continuous rainy conditions. For example, in April 2022, extreme and severe temperatures were experienced. The temperature in the north dropped below 0 degrees, and even snow and hail fell. Such a low temperature environment is very harmful to melon seedlings. After the watermelon is transplanted, the growing temperature should not be less than 10 to 15 degrees. If the temperature is too low, the soil is wet and cold in rainy days, and the sunlight is not enough, the growth of the watermelon seedlings' leaves will be restricted, the edges will be curled, and they will not be able to fully bend and stretch. There are very few canes, which can cause stiff seedlings.

The root system of watermelon is relatively shallow. When choosing a planting area, you need to choose sandy soil. The sandy flesh watermelon we usually eat is very sweet and grows in such a soil environment. However, some soils do not have many nutrients, and the roots of the melon seedlings cannot absorb many nutrients, which affects normal growth. As you can see from the picture below, the soil is white, has no nutrients, and is sticky. The soil is not fine enough. Under such conditions, it is difficult for the roots of the melon seedlings to come into close contact with the soil and digest it. There are not many nutrients, and the root growth is slow. After digging out the melon seedlings, observing the root system, you can find that the main root has grown very little and is very short. The root system is white in color and cannot absorb nutrients in the soil at all, causing the seedlings to grow slowly and become stiff.

Because watermelon originates from the tropical deserts of Africa, it likes continuous high temperatures and is not resistant to low temperatures. It will suffer from cold damage when encountering frost. It is generally believed that the suitable temperature for germination of watermelon seeds is 25-30°C. It is not easy to germinate within 15°C or above 40°C. The suitable temperature for the growth and development of the roots located in the upper part of the ground is 25-35°C, and the growth will be completely stopped if it is less than 10°C. In dry conditions, the temperature exceeds 48°C, or in humid conditions, the temperature exceeds 52°C, seriously affecting plant growth. Sunburn can occur under sustained high temperatures and strong sunlight. It is generally believed that the suitable temperature during the flowering period is 25°C. The higher the night temperature, the more stamens and fewer pistils.