Wrong watering is the most common cause of orchid leaves turning yellow.
1. Wet the orchid only in the morning.
2. The basic rule of watering frequency: once a week in winter and twice a week in summer.
3. Orchids in tight pots will be watered a little more often than those in larger pots.
4. The decision of a new watering isn’t made depending on how wet the substrate from the pot’s surface is. The substrate may still be moist inside. For extra safety, stick a wooden pencil inside the pot. If it feels moist after removal, it means watering should be cancelled.
5. Rainwater is the best, because in the fall it collects dust, pollen and other organic materials that contribute to plant nutrition. Tap water should be used with caution because it is subject to chemical treatments.
6. Orchids are watered always with room temperature water. Even if the effects are not immediate, watering with cold water causes serious physiological disorders that lead ultimately to the death of the plant.
7. Don’t water the orchid leaves. If you accidentally water them, remove the water with a paper towel.
8. Always keep dry the center of the rosette. Stagnation of water in the middle of the rosette is tantamount to a death sentence. If water somehow gets in there, remove it immediately with a paper towel or with ear sticks.
9. Excessive watering leads to leaves turning yellow, causing the plant to slowly die. If you notice signs of yellowing leaves and rotting roots, stop watering for several weeks.