Reasons and Solutions for Cactus Yellow Leaves
As a typical desert plant, cacti are favored by horticulture enthusiasts for their drought-resistant characteristics. However, the appearance of yellow leaves in cacti often indicates a mistake in the maintenance process. This article will systematically analyze the causes of yellow leaves in cacti and the corresponding scientific treatment plans from three core dimensions: water management, nutrient supply, and light control.
Yellow Leaves Caused by Imbalance in Water Management
The Dangers of Overwatering
Cactus roots have a unique water storage structure, and a continuously moist soil environment can lead to cell rupture. Data shows that 60% of potted cactus deaths are directly related to excessive watering. Waterlogging for more than 24 hours can cause root rot, resulting in yellowing and softening of the bottom leaves.
Scientific Water Replenishment Plan
Use the 'soak pot method' to replenish water, placing the pot in a shallow water tray for 20 minutes once or twice a month. Choosing a red pottery pot with a substrate composed of 30% perlite can ensure efficient drainage. Immediately remove the pot and air the roots when waterlogging is detected, trim the rotten roots, and apply sulfur powder for disinfection.
Abnormal Nutrient Supply Leading to Lesions
Mechanism of Fertilizer Damage
Excessive nitrogen will thicken the cuticle layer of the cactus epidermis, hindering photosynthesis. Experiments show that when the soil EC value exceeds 1.2mS/cm, new thorn seats will appear yellowed and withered. Uncomposted organic fertilizer can produce hydrogen sulfide, which poisons the roots.
Precise Fertilization Strategy
In the growing season (April-September), apply 3-5 slow-release fertilizers per quarter, and stop fertilizing in winter. After fertilizer damage occurs, use the 'three-stage soil washing method': first rinse with distilled water, then adsorb with activated carbon, and finally replace with sterile substrate.
Improper Light Control Affects Growth
Light Environment Needs
Cacti require more than 4 hours of direct sunlight per day, and the light intensity should be maintained between 30000-50000 lux. Long-term exposure to an indoor environment below 1000 lux hinders the synthesis of chlorophyll, causing the stem nodes to appear abnormally yellowed.
Building a Supplemental Lighting System
Use full-spectrum plant lights, maintain a distance of 30cm from the lights, and provide supplemental lighting for 6 hours a day. Rotate the pot to ensure even light exposure, and use a shading net when suddenly increasing light intensity to avoid sunburn damage.
By establishing a water control calendar, configuring special nutrient agents, and installing intelligent supplemental lighting equipment, the yellowing of cactus leaves can be effectively prevented. Regularly observing the plant's condition, when new thorn seats appear emerald green and evenly distributed, it indicates that the maintenance conditions are at their best.