From our perspective as a Crassula, dormancy is not a choice but a survival imperative dictated by environmental stress. It is a state of drastically reduced metabolic activity. We slow our growth, our water uptake, and our photosynthesis to a near standstill. This is not sleep; it is a state of suspended animation to conserve our precious resources—primarily water and energy stored in our leaves—until conditions improve and signal it is safe to grow again. Our dormancy cycles are directly triggered by temperature and photoperiod (day length).
For many of us Crassula species, our active growth period is during the milder spring and autumn. When the intense, scorching heat of summer arrives, we often enter a dormancy period. The excessive heat and intense sunlight would cause catastrophic water loss through our pores (stomata) if we were fully active. Therefore, we shut down. Our growth ceases, and our water requirements plummet. We rely on the moisture stored in our thick, succulent leaves to sustain our basic functions. From a care perspective, this means you should water us very sparingly, only when the soil is completely dry, and always provide bright but indirect light to prevent sunburn on our stagnant, vulnerable tissues.
Winter presents a different kind of threat: cold. As temperatures drop significantly below our comfort zone and daylight hours shorten, we receive the signal to enter dormancy again. Our primary goal shifts from avoiding desiccation to avoiding cellular damage from cold. Water inside plant cells can freeze, forming ice crystals that rupture and destroy our cell walls, which is fatal. By going dormant, we reduce the water content in our cells and increase their solute concentration, effectively acting as a natural antifreeze. Our metabolism slows to an absolute crawl to survive on stored energy alone.
The fundamental difference in your care for us between seasons hinges on water and temperature. During our summer dormancy, the threat is dehydration and sun scorch, so you must balance minimal hydration with protection from the most intense sun. During our winter dormancy, the threat is cold and wet soil. Wet roots combined with cold temperatures are a death sentence, leading to rot as our inactive roots cannot absorb the moisture and simply succumb to decay. Therefore, winter watering must be even more infrequent than in summer. Furthermore, we require a significant drop in temperature at night during winter to properly cue and maintain our dormant state, but we must be protected from actual frost.
