Analysis of the causes of yellow leaves in orchids and补救 techniques for yellow leaves in orchids.

Why Are the Leaves of the Orchid Turning YellowOrchid leaves turning yellow is a common problem in the maintenance process, which not only affects the ornamental value but may also endanger the plant's health. This article analyzes the six core causes and provides an exclusive rescue plan to help you accurately identify the root of the problem.I. Yellow Leaves Caused by Improper Water Management1.1 The Dangers of OverwateringOrchid's fleshy roots are extremely sensitive to waterlogging, and a continuously moist environment can lead to the asphyxiation and death of root hairs. Visible yellowing starts from the base of the leaves and gradually spreads to the tip, accompanied by moldy odor in the substrate.1.2 Scientific Watering PlanAdopt the "Three Observations" rule: observe the substrate (top 3cm dry), the season (reduce by half in winter), and the container (preferably breathable pots). It is recommended to use a mixed substrate of pine bark and volcanic rock (7:3) to ensure good drainage.II. Yellow Leaves Caused by Nutritional Imbalance2.1 Identifying Deficiency SymptomsNitrogen deficiency causes uniform yellowing of old leaves, while insufficient iron results in chlorosis between the veins of new leaves. It is recommended to apply orchid-specific slow-release fertilizer (NPK 20-20-20) monthly, combined with foliar application of chelated iron fertilizer (0.02% concentration).2.2 Emergency Treatment for Fertilizer BurnIf the leaf tips turn brown, immediately immerse the pot in water and rinse, changing the water three times consecutively to dilute the fertilizer. During the recovery period, use diluted 5000 times with brassinolide to promote root growth.III. Key Points of Light Adjustment3.1分级 Management of Light IntensityReceive full sunlight (20000-30000Lux) in spring and winter, and use double-layer shading nets (40% light transmission) in summer and autumn. Light-demanding varieties like Cattleya and shade-tolerant varieties like black orchids need to be treated differently.3.2 Sunburn Repair ProcessImmediately move to a shady place, retain the slightly yellowed leaves as natural sunshades, and cut off 1/3 of the severely sunburned leaves. Apply carbendazim powder to the cut to prevent infection.IV. Advanced Maintenance Techniques4.1 Air Humidity ControlMaintain 60-80% humidity using pebble water trays and a timed misting system. Be careful to avoid water accumulation on the leaves at night to prevent the occurrence of (T-J) disease.4.2 Root Health MonitoringCheck the roots every quarter; silver-white is a healthy state, while brown requires pruning. When repotting, retain 1/3 of the original soil to protect the roots and use boiled and disinfected planting material.Through systematic diagnosis and precise intervention, more than 90% of yellow leaf issues can be restored within two months. It is recommended to establish a maintenance log, record water, fertilizer, and light data, and gradually master the growth patterns of orchids. Regularly check the back of the leaves with a magnifying glass, address issues early, and restore the orchid's emerald-like luster.