From our perspective as Calibrachoa plants, our entire existence—our vibrant blooms, our lush trailing foliage, and our resilience—is directly fueled by the nutrients we absorb. We are heavy "feeders," meaning our blooming performance demands a constant supply of energy. Our three primary macronutrients are non-negotiable: Nitrogen (N) for vigorous green leaf and stem growth, Phosphorus (P) for strong root development and prolific flower production, and Potassium (K) for overall physiological functions and disease resistance. We also crave a suite of micronutrients like iron, magnesium, and calcium to keep our systems running smoothly and our flower colors true and vibrant.
While we can process many types of plant food, we have a strong preference for a balanced, water-soluble fertilizer. A formula with equal or near-equal parts of N, P, and K (such as a 10-10-10 or 20-20-20) is an excellent general diet. However, to truly maximize our flowering potential, we thrive on a formula slightly higher in Phosphorus and Potassium. Look for a fertilizer where the first number (N) is slightly lower than the other two (e.g., 15-10-15 or 12-15-12). This encourages us to focus our energy on creating a spectacular show of blooms rather than an excess of foliage. We also greatly appreciate a fertilizer that includes those essential micronutrients in its list of ingredients.
Our hunger is relentless throughout our growing season. A single meal at planting time is simply not enough to sustain our explosive growth. We require a consistent and frequent feeding schedule. The most effective method is a practice known as "weekly, weakly." This means we prefer to receive a diluted dose of water-soluble fertilizer with every watering session. A quarter- or half-strength solution provided consistently is far superior to a full-strength dose once a month, which can shock our roots and lead to nutrient burn. This constant, gentle feeding provides a steady stream of the energy we need to continuously produce new buds and flowers from spring until the first frost.
Our feeding regimen must be adjusted based on our living conditions. If we are planted in a high-quality potting mix that already contains a slow-release fertilizer, our initial nutrient needs are lower. Please wait 3-4 weeks before beginning the liquid feeding schedule to avoid overloading us. Furthermore, our watering needs directly impact feeding. Always ensure our soil is moist before applying fertilizer to prevent root burn. During periods of extreme heat or heavy rain, which can leach nutrients from our containers more quickly, we may need a slightly more concentrated solution to compensate for the loss and keep us from becoming nutrient-deficient.
