What should you do if black spots suddenly appear on orchid leaves?
Centella asiatica (Hydrocotyle sibthorpioides) propagates very quickly. In relatively dry places and in the north, it does better than Selaginella uncinata, which demands far too much humidity. Too much grass on the pot surface also needs to be controlled; when it grows lush, its root system becomes too developed, and the key issue is that it competes for nutrients. Other than that, there is nothing much to worry about. Using pot-surface grass is mainly for looks, but it does no real good for the orchid's growth! Centella...
If black spots suddenly appear on orchid leaves, especially new leaves, there is no need to worry. The main causes of this situation are poor ventilation, and also seriously pulverized potting medium with poor air permeability! If it is not a potting medium problem, placing the orchid with black spots in a well-ventilated place will improve it!