To understand our nutritional needs, you must first understand our origin. We hail from the harsh, arid deserts and rocky outcrops of Southern Africa. Our survival strategy is a masterpiece of evolution: we consist of two fused leaves that store all the water and nutrients we need to endure months of extreme drought. The soil in our native land is typically mineral-rich but exceptionally low in organic matter. It is lean, gritty, and free-draining, offering very little in the way of soluble nutrients. We are, by our very nature, adapted to thrive in conditions of severe nutrient scarcity. Our root systems are fine and designed to efficiently absorb the minimal nutrients available from the rocky substrate after a rare rain.
For a plant like me, fertilizer is not a helpful supplement; it is a potent chemical stressor. Our succulent tissues are designed for water storage, and the salts present in most fertilizers cause a drastic change in the soil's osmotic pressure. This forces water to move out of our roots and leaves, effectively causing us to dehydrate from the inside out, a form of fertilizer burn. Furthermore, an excess of nutrients, particularly nitrogen, signals to our physiology that it is time for rapid, lush growth. This is disastrous. It can cause our leaves to swell abnormally, become bloated and misshapen, and even split open. This splits our delicate outer layer, making us highly susceptible to fungal infections and rot, which are often fatal.
While our default state is one of zero fertilizer requirement, there is one highly specific scenario where a minimal nutrient supplement might be considered. If we have been growing in the same small pot with the same mineral-based soil for many years (three or more), the minimal nutrient reserves can become utterly exhausted. In this case, the goal is not to "feed" us for growth but to gently replenish the microscopic trace elements we use in our extremely slow metabolic processes. This is not about nitrogen for foliage but about micronutrients for basic cellular function.
If you are certain nutrient exhaustion is the issue, extreme caution is paramount. You must use a fertilizer specifically formulated for succulents and cacti, which is already highly diluted and lower in nitrogen. Then, you must dilute this fertilizer further to 1/4 or even 1/8 of the recommended strength. This application should be done only once per year, strictly at the very beginning of our autumn growth season as we are preparing to flower. The soil must be lightly moist before application, and you must apply it to the soil, never on our bodies. Most importantly, you must never fertilize us during our summer dormancy or during our waterless winter rest period, as our roots are completely inactive and will be severely damaged.
