The Reasons and Solutions for the Yellowing of Rieger Begonia Leaves
As an indoor plant with both ornamental leaf and flower value, the yellowing of Rieger begonia leaves has been a problem困扰ing many gardening enthusiasts. This article will systematically analyze the three major core causes and provide highly operable solutions to help you regain the lush pot plant scene.
Yellowing Caused by Temperature Imbalance
Analysis of Temperature Sensitivity Characteristics
The native temperate environment of Rieger begonia has formed its temperature-sensitive体质, with 22℃ being the critical growth value and 30℃ causing growth stagnation after 3 consecutive days. Laboratory data shows that under 28℃, the chlorophyll content in leaves decreases by 37%, which directly manifests as yellowing.
Precise Temperature Control Plan
It is recommended to use intelligent temperature control equipment, maintaining a range of 18-22℃ during the day and lowering 3-5℃ at night to simulate natural temperature differences. During high-temperature periods in summer, sunshades and atomizing humidification should be combined, which has been shown to reduce the leaf surface temperature by 5-8℃.
Yellowing Caused by Nutritional Imbalance
Mechanism of Fertilizer Damage
The diameter of Rieger begonia roots is only 0.2-0.5mm, with the upper tolerance limit of EC value being 1.8mS/cm. Over-fertilization (especially nitrogen fertilizer) can cause osmotic pressure imbalance, leading to root tip browning within 72 hours, which in turn affects nutrient transport.
Scientific Fertilization System
Adopt a strategy of "1/4 concentration, high-frequency" thin and frequent fertilization, applying balanced water-soluble fertilizer (N-P-K=20-20-20) at 500 times liquid every 10 days during the growing period. After fertilization, rinse the leaf surface with clean water to reduce salt residue.
Symptoms of Pest Infestation
Identification of Common Pests
Red spider mites (Tetranychus urticae) reproduce rapidly when humidity is <60%, and their piercing-sucking mouthparts can cause leaf discoloration. Microscopic observation shows that when the pest density reaches 15 per square centimeter, the leaf yellowing rate reaches 83%.
Comprehensive Control Plan
Implement a three-level protection of "physical + biological + chemical": hang yellow sticky traps to monitor pest situations, release Neoseiulus californicus for biological control, and alternately use dinotefuran and pyriproxyfen during pest outbreaks.
By precisely controlling temperature, scientifically managing nutrients, and systematically preventing pests, and by rotating the flowerpot regularly to ensure even light exposure, the yellowing problem of Rieger begonia leaves can be effectively prevented. It is recommended to conduct leaf microscopic examination monthly and adjust the maintenance plan in a timely manner to keep your begonia green and vigorous.