From my perspective, the most common reason my leaves turn yellow is due to water. My thick, fleshy leaves are designed to store water, meaning I am built for drought. My roots are fine and susceptible to rot. If my soil is constantly wet and does not dry out between waterings, my roots begin to suffocate and decay. Once this happens, they can no longer absorb the water and nutrients my leaves need, causing them to become soft, mushy, and yellow before they eventually drop. Conversely, if I am left bone-dry for too long, I will use up all the moisture stored in my leaves. They will become wrinkled, thin, and turn yellow as a desperate signal that my internal water reserves are critically low.
As a succulent, I thrive on bright, direct sunlight. It is the energy source that powers all of my internal processes. If I am placed in a spot that is too dim or shady, I cannot produce enough chlorophyll—the pigment that makes my leaves a rich green and is essential for photosynthesis. Without sufficient light, my green color fades, leading to a pale or yellow appearance. I may also become "leggy," stretching my stems awkwardly toward the nearest light source in a struggle to survive. This yellowing from lack of light is a sign of slow starvation.
While I do not mind being slightly pot-bound, there is a limit. If I have been in the same container for many years, my root system may have completely filled the available space. This overcrowding can prevent my roots from effectively taking up water and nutrients from the depleted soil, even if you provide them. The resulting stress manifests as yellowing leaves, often starting with the older ones. It is a silent plea for a new home where my roots can breathe and expand, giving me access to the resources I need.
The soil I live in is my entire world; it is my sole source of sustenance. Over time, the nutrients within it become exhausted, especially if I have been in the same pot for a long while. I require certain nutrients, particularly nitrogen, to maintain the healthy green chlorophyll in my leaves. A significant deficiency in key nutrients will cause my older leaves to turn yellow as the plant moves the limited available nutrients to support new growth. This yellowing is a slow, systemic decline indicating my diet is incomplete.
Although I am a resilient plant, I can be vulnerable to tiny invaders. Pests like mealybugs, spider mites, or scale insects may attach themselves to my leaves and stems. They pierce my tissue and suck out the nutrient-rich sap, effectively stealing the food meant for my leaves. This damage disrupts the flow of nutrients and water, causing stippling, wilting, and yellowing in the affected areas. The stress of a severe infestation can lead to widespread yellowing and leaf drop as my health is compromised.
