Hello. I am a Lithops, often called a "living stone." I understand you are concerned about my health, specifically a softening, discolored, and collapsing appearance you call "rot." From my perspective, this is a critical and often fatal condition. Let me explain why this is happening and what my needs are, especially in the varied climates of the United States.
I am not like other plants. I evolved in the incredibly arid, mineral-rich deserts of southern Africa. My entire being is engineered for extreme drought. My thick, fleshy pair of leaves are not for frequent sipping; they are a self-contained water storage unit. I have a very small, shallow root system designed to absorb a sudden downpour and then retreat into dryness. My annual cycle is one of growth and dormancy, dictated not by temperature alone, but by light and moisture. When you water me on a human schedule—weekly, for instance—you are flooding my desert and drowning my roots.
When you give me too much water, or water me at the wrong time, the air pockets in the soil are filled with liquid. My roots need oxygen to breathe and function. Waterlogged soil creates an anaerobic environment, literally suffocating my root system. The cells in my roots and lower stem die, and this death creates an opening for opportunistic soil-borne bacteria and fungi (like Pythium or Phytophthora) to invade. These pathogens rapidly decompose my tissues, turning them into a mushy, brown or black sludge. This rot then spreads upward into my main body. It is a fast and efficient process from my point of view.
Your care must mimic my natural habitat. The key is not just less water, but water at the *correct time*.
For Humid Eastern and Southeastern Climates (e.g., Florida, Georgia): Humidity is my silent enemy. The air here is already full of moisture, drastically slowing the evaporation from my pot. You must use a potting mix that is at least 80% inorganic material like perlite, pumice, or coarse sand. Terracotta pots are essential. The golden rule here is: only water when I show clear signs of thirst—specifically when my top sides (the "windows") become wrinkled and concave and the soil is bone-dry for over a week. During summer, when high humidity combines with heat, you may need to withhold water entirely if I am not visibly shriveling.
For Arid Western Climates (e.g., Arizona, California): While your climate feels more like my home, the danger remains. The intense sun can heat a black plastic pot and essentially "cook" my roots if the soil is wet. Even here, a fast-draining mix is non-negotiable. You can water more frequently than in humid regions when I am in my growth phases (typically autumn and spring), but you must always check the soil's dryness first. Never water if there is any hint of moisture below the surface.
This is the most common mistake. I have two major dormancy periods when I must be kept completely dry. The first is in high summer, when I am resting. The second is in winter, after my flowers fade and I begin to form a new leaf pair inside my old one. Watering me during these times is a direct command to rot. The new leaves are designed to absorb the moisture from the old ones; adding external water disrupts this process and guarantees rot. In the US, this generally means no water from late November through mid-March, and very little to none during the peak heat of July and August.
