What is the best time to fertilize crops?

The most suitable time to fertilize orchid plants is the day after watering, when the temperature is above 15°C and below 30°C, and there is light. This is because after watering, both the substrate and the roots are still moist, so the orchid plants will not be at risk of fertilizer burn from rapidly absorbing the fertilizer solution while too dry. At low temperatures, the plant's physiological activity slows down and it is in a semi-dormant state, mostly not absorbing fertilizer; at high temperatures, water evaporates quickly, the concentration of residual fertilizer rises relatively, and there will be some side effects; on cloudy and rainy days, air humidity is high, water does not evaporate easily, and the roots do not easily absorb fertilizer. Only when the light is mild is it most suitable to apply fertilizer. Likewise, this is also the most suitable time for foliar feeding. In order to improve the effect of foliar feeding, it should also be chosen to spray at 16:00-17:00 on a sunny day. This is because at this time the light is weak, so fertilizer damage is unlikely; moreover, the leaf stomata are open, giving more opportunity for absorption. In addition, the night dew, soil moisture, and high-humidity air can also help the fertilizer solution clinging to the leaves to move, thereby increasing the chance of absorption. (Xu Dongsheng)