What to Do When榕 Tree Leaves Turn Black
As a star variety of indoor green plants,榕 trees are deeply loved for their unique aerial root shapes. However, the common problem of black leaves during maintenance has troubled many plant enthusiasts. This article will systematically analyze the four main causes of black leaves in榕 trees, from environmental regulation to pest and disease control, and provide corresponding solutions.
Key to Environmental Humidity Control
Hazards of Excessive Water
榕 tree roots are extremely sensitive to waterlogging. When the potting soil humidity is >70% for more than 3 days, the closure of stomata can lead to black veins in the leaves. You can check the humidity using the bamboo stake method: insert the stake into the potting soil for 2 hours, and if the moist part exceeds 1/3, it is necessary to control the water.
Scientific Watering Plan
In spring and autumn, water thoroughly every 7-10 days, in summer reduce to every 5-7 days, and in winter extend to every 15-20 days. It is recommended to use a humidity meter to monitor and maintain the environmental humidity between 50-65%. In the northern heating season, you can spray water daily to increase humidity.
Measures to Protect Against Temperature Fluctuations
Control of Temperature Difference Threshold
A temperature difference of >8°C between day and night may cause the leaf edges to blacken, so avoid placing the plant near doors and windows where there is air flow. In winter, the night temperature should be kept above 15°C, and the pot-in-pot method can be used to buffer the high temperature of floor heating.
Coordination of Light Management
In summer, use a shade net to filter 50% of the light from 10:00 to 15:00, and in winter ensure 4 hours of direct sunlight daily. When suddenly changing the lighting environment, a gradual transition method should be used.
Comprehensive Management of Pests and Diseases
Recognition of Pest Characteristics
Scale insects can cause sticky secretions on the back of leaves, spider mites cause yellow spots on the leaf surface, and aphids tend to gather on tender buds. It is recommended to check the leaf axils weekly with a magnifying glass and isolate any pests found immediately.
Biological Control Plan
Release ladybugs to control aphids and use predatory mites to fight against spider mites. For chemical control, recommend a compound preparation of matrine and azadirachtin, and spray preventively once a month.
Precise Fertilization Strategy
Key Points of Fertilizer Ratio
In the growing season, use a water-soluble fertilizer with N-P-K=10-6-8, and keep the concentration between 800-1000 times. In late autumn, apply monopotassium phosphate (0.2% concentration) to enhance cold resistance, and remember the principle of applying thin and frequent fertilization.
Tips for Fertilizer Damage Repair
If the leaf tips turn black, stop fertilizing immediately and flush with large amounts of water for 3 consecutive times to remove salt. Retain 1/3 of the leaf area of the damaged leaves and wait for new buds to sprout before pruning to avoid secondary damage.
By precisely controlling temperature and humidity, preventively managing pests and diseases, and applying scientific fertilization, combined with regular pot rotation (every 15 days rotate 90 degrees) and root checks (change pots every spring), the problem of black leaves in榕 trees can be effectively prevented. It is recommended to establish a maintenance log to record each watering and fertilizing, gradually mastering the growth patterns of the plant.