Greetings. I am a cactus, a proud resident of some of the planet's most challenging environments. My survival depends on a finely tuned cycle of growth and rest, dictated not by a calendar, but by the sun and temperature. You wish to understand my dormant period and how to best support me through it. From my perspective, it is a time of deep, quiet introspection and conservation, and your care is crucial.
I do not experience dormancy in a single, uniform block. It is triggered by two key environmental shifts that signal the end of my prime growing season. The most significant cue is the drastic reduction in light intensity and daily photoperiod as autumn progresses into winter. With less potent sunlight, my photosynthetic engine, which is my way of creating food, slows down considerably. The second trigger is a sustained drop in temperature, particularly at night. While many of us are tolerant of cool weather, consistently cold conditions, especially when combined with wet soil, are a direct threat to my core. To survive, I must enter a state of suspended animation. This period generally aligns with the fall and winter months, but it can begin as early as late September and extend through March, depending on your local climate and whether I live indoors or out.
This is the most critical adjustment you must make. During my dormancy, my metabolic processes are operating at a tiny fraction of their summer capacity. I am simply not using water. My roots, which are designed to absorb moisture rapidly when it's available, are now vulnerable to rot in cold, wet soil. If you water me as you do in summer, you will essentially drown me in my sleep. From my perspective, you should withhold water almost completely. For many of my kind, a deep, thorough watering once in late autumn and perhaps one very light one in mid-winter if I show signs of severe shriveling is all that is needed. The goal is to prevent my tissues from desiccating completely without ever allowing my substrate to become truly damp.
Dormancy is not a dark, closet-bound affair. I still crave bright, indirect light. A south-facing windowsill is ideal for my potted brethren. This light, though weaker, helps maintain my basic health and prevents etiolation—a weak, stretched growth that occurs when I desperately search for a light source. Furthermore, a period of coolness is essential. It solidifies my dormancy, making it complete and restful. An ideal temperature range for this rest is between 35°F and 55°F (2°C and 13°C). A cool garage, a bright porch, or an unheated room that stays above freezing is perfect. This chilly period is what ultimately stimulates me to produce a magnificent display of flowers when the growing season returns.
Please, do not feed me. Fertilizer is a signal to grow, a command my body cannot and should not obey during my rest. My system cannot process those nutrients, and the salts can build up in the soil, damaging my sensitive roots. This is also a time to leave me be. Do not repot me. The energy required to repair damaged roots and establish in new soil is energy I do not have and cannot spare. Repotting should only be done as I am waking up in the spring, when my energy reserves are ready to be mobilized for new growth.
