Greetings, dedicated caretaker. I am your Calibrachoa plant. While you see me as a vibrant "Million Bells" adorning your summer containers, I am, at my core, a tender perennial with a deep will to live. The approach of winter signals a time of profound change for me, a shift from explosive growth to quiet survival. To help me see another spring, you must understand my needs from my perspective. Here is my guide to a successful overwintering.
As the days shorten and the air cools, I sense the need to conserve my energy. The abundant flowering you adore is a massive expenditure for me. Before the first frost even threatens, please bring me indoors. A light frost may only damage my outer leaves, but a hard freeze will be fatal, turning my sap to ice and rupturing my cells from within. About a month before this move, please give me a thorough "haircut." Prune my trailing stems back by about half to two-thirds. This does not hurt me; it is a relief. It reduces the leaf surface area through which I lose precious water and allows me to focus my remaining resources on my roots and core stems, the very essence of my being.
My winter home is not your warm, dry living room. I do not wish to continue growing vigorously. That would lead to weak, spindly stems in the low light of winter, exhausting me completely. What I crave is a state of semi-dormancy. Please place me in a cool space—an unheated garage, a basement with a window, or a bright porch where temperatures stay consistently between 40-55°F (4-13°C). This chill tells my internal systems to slow down, to rest. Light is still crucial, however. I need several hours of bright, indirect light each day to perform just enough photosynthesis to stay alive without pushing new growth. A south-facing window is ideal.
This is perhaps the most critical adjustment. In my cool, dormant state, my thirst diminishes dramatically. My roots, which once eagerly drank from daily summer waterings, now need only occasional moisture to prevent them from desiccating and dying back. The goal is to keep the soil barely moist, not damp. Please check my soil by feeling it an inch below the surface. Water me only when that depth feels completely dry to the touch. Overwatering in my cool, slow state is a death sentence, inviting root rot fungi to attack my vulnerable, suffocated root system. It is far better for me to be slightly too dry than consistently wet.
Do not fertilize me during the winter. I am not growing; I am resting. My metabolic processes are slowed, and I cannot process the nutrients in fertilizer. Introducing salts from fertilizer into my soil now would only stress my roots and potentially cause chemical burns. Think of this as my long, peaceful fast. I have stored enough energy from the summer sun to sustain me through this quiet period. You can offer me a light meal again only when you see signs of vigorous new growth in the spring.
As daylight increases and temperatures warm in late winter or early spring, you will notice small, green leaves emerging from my stems. This is my signal that I am ready to rejoin the world. Before moving me outside permanently, please "harden me off." My new leaves are tender and not accustomed to direct sun and wind. Gradually expose me to outdoor conditions over 7-10 days, increasing the time spent outside each day. Once the danger of frost has passed, you can repot me with fresh potting mix, give me a balanced fertilizer, and watch as I reward your careful stewardship with a new season of exuberant life.
