What Causes the Dry Leaves of矮牵牛 (Petunia)
As one of the favorite ornamental flowers for gardening enthusiasts, the issue of withered leaves in矮牵牛 often confuses growers. This article systematically analyzes the four most common causes and corresponding solutions to help you quickly diagnose the plant's condition and restore its vitality.
One: Abnormal Soil Environment
1.1 Acid-alkaline Imbalance Damage
矮牵牛 thrives in slightly acidic soil with a pH of 5.5-6.5. When soil alkalinity is detected to be excessive (pH>7), it hinders the absorption of trace elements such as iron and zinc by the roots, leading to interveinal yellowing and leaf curling and drying. Alkaline soil also destroys microbial communities, affecting the decomposition of organic matter.
1.2 Improvement Solution
Suggested to use a mix of peat soil + decomposed leaf soil + perlite (5:3:2) as the substrate. For emergency treatment, pour a dilute solution of white vinegar (1:1500) monthly to adjust the pH, or mix sulfur powder evenly into the topsoil at 30g/m².
Two: Deficiency of Nutrient Elements
2.1 Iron Deficiency Chlorosis
2.2 Scientific Iron Supplement Techniques
It is recommended to use chelated iron fertilizer (EDTA-Fe) sprayed on the leaves according to the instructions, combined with root watering with a mixture of iron sulfate and cake fertilizer (1:3:100 fermentation solution). This dual approach yields better results. Avoid mixing with alkaline fertilizers.
Three: Imbalance of Temperature and Humidity
3.1 Damage from Dry Air
When the environmental humidity is below 50%, the plant's stomata close, leading to hindered transpiration, manifested as wilted leaves and leaf tip scorching. Prolonged dryness can also trigger pests such as spider mites, exacerbating leaf damage.
3.2 Humidity Control Solution
Suggested to use a hygrometer to monitor in real-time and an ultrasonic humidifier to maintain 60-70% humidity. For simple maintenance, place a water-filled saucer under the pot with ceramic stones soaked in water to form an evaporation layer, avoiding direct spraying of water on the flowers.
Four: Improper Light Management
4.1 Sunburn Symptoms
Exposure to light intensity exceeding 50,000 lux during noon in summer can cause yellowish-brown sunburn spots on the leaves, and in severe cases, the whole leaf can wither and fall off. However, long-term shading (＜8000 lux) can cause etiolation.
4.2 Scientific Lighting Strategy
Receive full sunlight in spring and autumn, and use a 50% shade net to filter strong light in summer. It is recommended to use smart grow lights to control the light intensity between 25,000-35,000 lux, ensuring 6-8 hours of light exposure daily.
By systematically checking the four core elements of soil pH, nutrient supply, environmental humidity, and light intensity, combined with scientific diagnosis and precise adjustment,矮牵牛 can recover to a healthy state within 30 days. It is recommended to establish a maintenance log to record the changes in the plant after each adjustment, gradually mastering its growth patterns. Regular use of soil testers and plant nutrient solutions can prevent more than 85% of leaf abnormality issues.