What to Do When Banyan Bonsai Leaves Turn Yellow and Fall Off
Banyan bonsai leaves turning yellow and falling off is a common issue during maintenance, although this plant has strong adaptability, its root system is highly sensitive. Abnormal leaf drop often indicates root damage, environmental imbalance, or pest and disease attacks. This article systematically reviews 5 emergency measures, using specific case analysis to help you quickly identify the root causes of the problem.
One, Core Techniques for Water Management
1.1 Accurate Control of Watering Amount
Use the 'Three-Finger Detection Method': Insert the index, middle, and ring fingers into the potting soil to a depth of 2-3cm; if only the fingertips touch the soil, it indicates immediate watering is needed. In summer, it is recommended to check twice a day, early morning and evening, while in winter, this can be extended to every 3 days.
1.2 Upgrade Solution for Drainage System
Lay a 3cm thick layer of volcanic rock at the bottom of the pot, combined with a 1cm diameter drainage hole, to increase drainage efficiency by 30%. Special note: Additional side wall ventilation holes need to be added when using glazed ceramic pots.
Two, Full Process of Root Repair
2.1 Standard for Identifying Rotten Roots
Healthy roots should be milky white with a fresh earthy scent; when brown, slimy tissue appears along with a sour smell, immediate surgical treatment is needed. It is recommended to retain uninfected roots with a diameter >2mm as a basis for regeneration.
2.2 Disinfection and Regeneration Technique
Soak in 3% hydrogen peroxide for 15 minutes instead of the traditional myclobutanil, which can kill 99% of anaerobic bacteria. After surgery, it is recommended to use a gibberellin (50ppm) solution to promote new root growth, increasing success rate by 40%.
Three, Three-Dimensional Pest and Disease Control
3.1 Early Warning Signals of Diseases
Immediate isolation is needed when white powdery substance appears on the back of leaves (early sign of powdery mildew), ring-shaped brown spots on the leaves (characteristic of T-J disease), or gel-like substance oozes from the branches (sign of ulcer disease), and use the corresponding biological agents.
3.2 Physical Control of Pest Infestation
Hanging yellow sticky boards can capture 80% of adult aphids, and combined with weekly garlic extract spray (1:50 concentration) on the leaf surface, it can effectively control egg hatching. In severe infections, it is recommended to use plant-derived pesticides such as azadirachtin.
Four, Environmental Optimization Strategies
Maintaining a day-night temperature difference of 8-10°C can enhance stress resistance, using LED full-spectrum grow lights for 4 hours daily, and maintaining air humidity between 60%-70% through an ultrasonic humidifier.
Five, Soil Improvement Solution
Change the mixed substrate containing 30%鹿沼土 (Bokai soil) + 40%赤玉土 (Akadama soil) + 30%腐叶土 (decomposed leaf soil) every half a year, and add 5% bone meal as a slow-release fertilizer source. Regularly test the EC value to keep it between 0.8-1.2mS/cm.
By systematically implementing the above maintenance plan, 90% of yellow leaf issues can be significantly improved within 2-3 weeks. Special reminder: Do not apply any chemical fertilizers before the new leaves are fully unfolded, as maintaining a stable environment is the key to recovery. It is recommended to keep a maintenance log, recording key parameters such as temperature, humidity, and watering frequency, to form a personalized maintenance plan.