My most common reason for dropping leaves is an imbalance in my water supply. I am a succulent, which means my thick, fleshy leaves are designed to store water for long periods. If you water me too frequently, my roots will sit in soggy soil and begin to rot. Once they rot, they cannot deliver water and nutrients to the rest of my body. In this state of drought-from-within, my older leaves will soften, turn yellow, and drop off to conserve resources for my core stem. Conversely, if you forget to water me for a very long time, I will use up all the stored water in my leaves. They will become shriveled, dry, and crispy before falling off. This is my way of sacrificing parts of myself to keep the main plant alive.
I am a creature of habit and thrive on stability. Sudden changes in my environment are a significant shock to my system, triggering a stress response where I shed leaves. This is often called "transplant shock" if I have been recently repotted, even if it was for my own good. A drastic move from a shady spot to direct, hot sunlight (or vice versa) can also cause this. Similarly, being brought indoors for winter or moved to a new location with different temperature and light levels forces me to adapt. Leaf drop is my way of adjusting my foliage mass to better suit the new conditions, but it is a sign that the change was too abrupt.
While I can tolerate a range of light conditions, I truly need bright, indirect light for several hours a day to perform photosynthesis efficiently. In low light conditions, my internal energy production grinds to a slow pace. I cannot sustain all of my leaves with the limited energy I make. To survive, I must make a difficult choice: I will actively abort my older, lower leaves that are perhaps shaded by new growth or are less efficient. This allows me to redirect my limited energy reserves to maintaining my stem and growing just a few new leaves that are better positioned to catch the available light.
Over time, I can outgrow my pot. When my root system becomes pot-bound—a dense, tangled mass that has exhausted the available soil and nutrients—it struggles to function properly. It cannot uptake water and nutrients effectively, even if they are present. This creates a situation similar to underwatering, where I am unable to hydrate my leaves properly. Furthermore, the lack of space for new root growth stifles my overall health. In this state of stress and malnutrition, I will begin dropping leaves because I simply cannot support them with my compromised root system.
Although less common, I can be attacked by pests like mealybugs or spider mites. These tiny creatures suck the sap directly from my leaves and stems, robbing me of my vital fluids and weakening my structure. An infestation can cause my leaves to become stippled, yellow, and eventually drop. Furthermore, a fungal or bacterial disease, often stemming from overly wet conditions, can attack my stem or roots. As the disease disrupts my vascular system, it prevents water movement, causing leaves to wilt, blacken, and fall off as the illness progresses.
