Reasons and Solutions for Yellowing Leaves of Nail Orchid
As an elegant epiphytic orchid plant, the nail orchid is widely favored for its graceful inflorescence and rich fragrance. However, yellowing leaves often plague orchid enthusiasts during the maintenance process. This article systematically analyzes the causes from four core elements and provides professional solutions.
I. Yellowing Leaves Caused by Improper Light Management
1.1 Typical Manifestations of Insufficient Light
When the light intensity is below 2000 lux, the leaves cannot perform photosynthesis normally, and the synthesis of chlorophyll is hindered, leading to yellowing. Especially the growth rate of new leaves will decrease by 40%-60%, accompanied by the phenomenon of elongated leaf spacing.
1.2 Scientific Light Supplement Plan
It is recommended to use double-layer shading nets to adjust, maintaining a 30% shading rate in spring and autumn and increasing to 50% in summer. It can be hung 1.2 meters away from the east-facing windowsill, receiving 4-6 hours of gentle light daily. In winter, full-spectrum LED grow lights can be used to supplement light for 2 hours daily.
II. Imbalance in Temperature Control Affects Metabolism
2.1 Temperature Sensitivity Characteristics
The optimal growth temperature range for nail orchids is 18-28°C. When the day-night temperature difference is less than 5°C or more than 10°C, cell metabolism is disrupted. High temperatures above 35°C can accelerate transpiration and cause dehydration, while temperatures below 10°C trigger cold injury responses.
2.2 Four-Season Temperature Control Strategies
In summer, use a water curtain cooling system, combined with morning and evening misting to maintain humidity above 65%. In winter, use a constant temperature heating mat to maintain the substrate temperature above 15°C. During the transition season, be careful to avoid direct blows from air conditioners.
III. Synergistic Water and Fertilizer Supply Plan
3.1 Accurate Irrigation Cycle
Use the "wet-dry alternation" method during the growing period, soaking the pot for 15 minutes after the surface of the sphagnum moss turns white. The air humidity needs to be stabilized between 60%-75%, and an automatic misting system can be configured, misting for 10 seconds every 2 hours.
3.2 Scientific Fertilization Ratio
Use orchid-specific fertilizer with an EC value of 1.2-1.5mS/cm and an N-P-K ratio of 20-10-20. Spray on the leaves weekly from April to October, combined with a monthly application of seaweed acid root drenching, and stop fertilizing during the dormant period.
IV. Substrate Improvement and Root Care
4.1 Ideal Substrate Formula
It is recommended to use a layered structure: a 2cm layer of ceramic stones at the bottom for drainage, a 5cm middle layer of pine bark (1-1.5cm particle size) mixed with charcoal (3:1 ratio), and a top layer of live sphagnum moss. Replace the new substrate every spring.
4.2 Root Health Monitoring
Check the roots every quarter; silver-white fleshy roots indicate a healthy state. If brown rotting roots are found, trim them immediately and soak in a 0.1% potassium permanganate solution for disinfection. After repotting, place it in a shady place to harden off for 7 days.
Through systematic light regulation, precise temperature and humidity management, scientific water and fertilizer supply, and substrate optimization, the yellowing leaf problem of nail orchids can be effectively prevented and improved. It is recommended to establish a maintenance log, recording environmental parameters and plant responses, gradually mastering its growth patterns. Regularly use a magnifying glass to observe the back of the leaves to detect the early signs of pests and diseases, and use biological control to maintain plant health.