TheNaturePlanet

If Phalaenopsis (moth orchids) are not properly cared for after repotting, problems such as yellowing leaves may easily occur. Today, let's discuss the reasons behind leaf yellowing after repotting and the corresponding solutions.
Common Reasons for Leaf Yellowing After Repotting Phalaenopsis
Nutrient Deficiency
The root system has not yet restored its absorption capacity after repotting, so the plant consumes its own stored nutrients.
Improper Light Exposure
Failure to provide timely shade after repotting leads to leaf burns from strong direct sunlight.
Pests and Diseases
Improper handling during repotting or unsterilized potting media can trigger fungal or bacterial infections.
Issues with Sphagnum Moss
Planting too deeply with sphagnum moss causes root suffocation, or excessive watering/long-term moisture in the media leads to root rot.
Incorrect Watering
Watering at noon shocks the roots, or an unreasonable watering frequency disrupts root health.
Fertilization Errors
Applying fertilizer before the plant has stabilized causes root burn.
Post-Repotting Care Tips
Repotting Timing
Avoid high-temperature periods. If repotting is necessary, retain the original sphagnum moss to minimize root damage.
Potting Media and Pot Selection
Use breathable and water-retentive media, such as a mix of bark and sphagnum moss.
Choose a pot that is only 1 cm larger than the original pot. Avoid large or deep pots, as they slow down the drying-wetting cycle and cause root rot.
Key Precautions
Prevent air roots or deep planting: Ensure roots are firmly in contact with the media, and do not bury the base of the pseudobulbs.
During the acclimation period (1-2 weeks): Do not fertilize. Water thoroughly only when the sphagnum moss is completely dry, and water in the morning or evening at low temperatures. Ensure good ventilation after watering.
Light and temperature: Place the plant in a spot with diffused light (avoid direct sunlight). Maintain a warm environment (20-28°C) with good air circulation.
Solutions for Yellowing Leaves
Mild Yellowing
Immediately move the plant to a location with diffused light. Check the moisture level of the sphagnum moss, water only when dry, suspend fertilization, and inspect the root health.
Root Rot
Remove the plant from the pot, trim rotted roots, soak in a carbendazim solution for 10 minutes, air-dry, and replant with fresh, sterilized media. Do not water immediately; wait 1-2 days before giving a small amount of water.