Waterlogged soil is the quiet catastrophe behind most dying succulents. These plants evolved in arid habitats where brief rains drain or evaporate quickly, leaving roots surrounded by air, not persistent moisture. When a pot stays wet, liquid floods every pore in the substrate, displacing oxygen that roots and beneficial microbes need for aerobic respiration. What looks like care at the surface becomes oxygen debt below it.
Without gas exchange, root cells shift into anaerobic metabolism, a biochemical dead end for tissue designed for dry cycles. Starved of oxygen, roots lose structural integrity, their membranes break down, and the plant can no longer regulate water uptake or ion transport. Saturated conditions also favor opportunistic pathogens; fungi and bacteria that drive classic root rot exploit this low-oxygen, high-moisture niche. The plant responds to hydraulic stress by yellowing, swelling, and then collapsing, not because it was thirsty, but because its survival strategy depends on intervals of desiccation. In a sense, drought is its home ground; constant water is the foreign environment that turns a survival adaptation into a fatal liability.
For growers, the practical threshold is not emotion but physics: porosity, drainage, and evaporation rate determine whether each watering restores a cycle or locks the plant into anoxic stagnation. The same water that sustains photosynthesis in the leaves can, if trapped, erase the subterranean architecture that makes photosynthesis possible at all.
