From my perspective as a Crassula, my plump, juicy leaves are my pride and my reservoir. They are designed to store water for dry periods. When I am not given enough water for an extended time, I am forced to tap into these internal reserves. As the water within my leaf cells depletes, the tissues begin to shrink and lose turgor pressure. The vibrant green chlorophyll, essential for my photosynthesis, breaks down. What becomes visible are the underlying yellow pigments, the carotenoids. You will notice my leaves turning yellow, often starting at the lower, older ones, and they will feel limp, thin, and may even wrinkle. The fix is simple: a thorough, deep watering. Please soak my soil until water runs freely from the drainage holes, allowing my roots to drink their fill. Then, let the soil dry out almost completely before the next watering.
This is the most common and dangerous threat I face. While I am drought-tolerant, my roots absolutely despise sitting in constantly soggy soil. When overwatered, the air pockets in the soil are flooded, suffocating my root system. My roots need oxygen to breathe, and without it, they begin to die, turning soft, dark, and mushy—a condition you call root rot. Once this happens, the compromised roots cannot absorb water or nutrients, no matter how wet the soil is. Essentially, I begin to die of thirst while standing in water. The yellowing leaves in this case are a sign of starvation and stress. They will typically be soft and mushy themselves, and the yellowing may affect leaves all over my body, not just the older ones. To save me, you must act quickly. Remove me from the wet soil, trim away all the black, rotten roots with a sterile tool, and repot me into fresh, dry, well-draining succulent mix. Do not water me for at least a week to allow my root system to heal.
As a sun-worshipper, I need bright, direct light for several hours a day to thrive. This light is the energy source that powers my food production (photosynthesis). When I am kept in a spot that is too dim, my internal systems go into crisis mode. To survive, I must conserve energy. One way I do this is by reducing the production of chlorophyll in my leaves, as maintaining it is energetically costly. With less green chlorophyll, the yellow pigments become more prominent, leading to an overall pale or yellowish appearance, a process called etiolation. My stems may also become stretched and leggy as I desperately reach for any available light source. The solution is to gradually acclimate me to a brighter location, such as a south-facing window. Please do not move me abruptly from deep shade to intense, direct sun, as this can scorch my leaves, causing another form of damage.
If you have recently repotted me, a few yellowing leaves might simply be my response to the move. Being transplanted is a significant physical disturbance. My root system is delicate, and even careful handling can cause minor damage and shock. As I focus my energy on establishing new roots in the fresh soil, I may sacrifice some of my older leaves. The resources within these leaves are reabsorbed to fuel new root growth. This is a natural process. The yellowing is usually confined to a small number of the lower, mature leaves and should not spread rapidly. The best thing you can do is to place me in a stable environment with appropriate light and refrain from watering for a few days to allow any root abrasions to callus over. I should recover on my own as I settle into my new pot.
While I am not a heavy feeder, I do require some nutrients, especially nitrogen, which is a core component of chlorophyll. If I have been growing in the same soil for many years, the available nutrients can become depleted. Without sufficient nitrogen, my ability to produce chlorophyll is hampered, leading to a general chlorosis, or yellowing, of the leaves, often starting with the older ones. This yellowing is typically more uniform than that caused by water issues. To address this, you can feed me with a diluted, balanced fertilizer formulated for succulents or cacti during my active growing season (spring and summer). Please be cautious not to over-fertilize, as a buildup of salts can also damage my roots and cause similar symptoms.
