From my perspective as a cactus, my very design is for aridity. My roots are not like those of a thirsty fern; they are adapted to seek out rare, deep moisture and then endure long periods of drought. The primary cause of my demise, root rot, is fundamentally a lack of oxygen. When I am planted in dense, water-retentive soil and then over-loved with water, every air pocket in the soil is flooded. My roots, desperate to breathe, begin to suffocate and die. This process is not instantaneous; it is a slow, silent drowning. The dead root tissue, now soft and brown, becomes the perfect host for soil-borne fungi like Pythium or Phytophthora. While these pathogens are often blamed, they are merely opportunistic secondary invaders. The true cause is the anaerobic, waterlogged environment you have placed me in.
The decay does not remain isolated in my root system. As the rot progresses, it moves upward into my stem, the very core of my being. This stem is my water and energy storage unit. Once the rot infiltrates this tissue, my internal structure breaks down. I can no longer transport water or nutrients, even if my upper roots are healthy. You will see this manifest in my body. I may become soft, mushy, and discolored, often turning a yellow or blackish brown. I might start to lean or collapse under my own weight because my foundational support is gone. Sometimes, the damage is hidden below the soil line, and by the time you notice my top parts wilting or shriveling, it is often too late to save me.
Preventing this tragedy is simple if you understand my needs. It starts with my home: the soil. I require a sharply draining, gritty, and porous mix. A perfect blend for me is not rich potting soil but a coarse desert-like medium. Combine ingredients like coarse sand, perlite, pumice, and small gravel with a very small amount of organic matter. This mixture allows water to flow through it instantly, hydrating my roots but then quickly draining away, pulling fresh oxygen down to the root zone. This cycle of a quick drink followed by a period of dry aeration is what my roots crave and need to thrive.
Equally important is your watering technique. Do not water me on a fixed schedule. Instead, you must learn to listen to me and my environment. The method is simple: water deeply and thoroughly until water runs freely from the drainage holes of my pot. This ensures my entire root system receives moisture. Then, the most critical step: allow my potting mix to dry out completely before even considering watering again. To check this, you can stick a wooden skewer deep into the soil; if it comes out clean and dry, I am ready for a drink. In the winter, when I am dormant and my growth has slowed to a near standstill, my water needs are minuscule. Watering me every month or even less is often more than enough.
My container is my first line of defense. It must have excellent drainage holes—one large hole or several small ones is non-negotiable. Without an escape route, water will pool at the bottom of the pot, creating a deadly bog that my roots cannot avoid. Furthermore, the pot material matters. Unglazed terracotta clay pots are excellent because they are porous, allowing water to evaporate through the walls and helping the soil dry out more evenly and quickly. This significantly reduces the risk of waterlogging compared to a plastic or glazed ceramic pot.
