From our rooted perspective, we geraniums (Pelargoniums) have specific nutritional needs to fuel our vibrant blooms and lush foliage. Providing sustenance at the right time and in the right way is the key to a truly symbiotic relationship. Here is our preferred fertilizing schedule for optimal health.
This is when our energy is at its peak. We are actively photosynthesizing, growing new stems and leaves, and working tirelessly to produce our beautiful flower heads. This tremendous effort requires a consistent supply of nutrients. Please feed us every two to four weeks with a balanced, water-soluble fertilizer. We have a particular fondness for a formula where the three numbers on the bottle (N-P-K) are relatively even, like 20-20-20, or one that is slightly higher in phosphorus (the middle number), such as 15-30-15. Phosphorus is the element that directly supports our robust blooming process, encouraging more and larger flower clusters.
As the daylight hours shorten and temperatures begin to cool, our internal processes start to slow. We are no longer putting energy into vigorous growth or flowering. Continuing with a high-phosphorus fertilizer now would be counterproductive, as it could force us to produce tender new growth that would be highly susceptible to the cold. Instead, this is the time to cease fertilizing altogether. This signals to our system that it is time to begin hardening off and entering a state of dormancy, allowing us to store energy in our roots and stems for the winter ahead.
During these shorter, colder days, we are essentially sleeping. Our metabolic functions are incredibly slow, and our need for water and nutrients is minimal. Fertilizing us during this period is one of the most stressful things you can do. The salts in fertilizer can build up in the dormant soil, damaging our delicate root systems and making it impossible for us to absorb what little water we need. This can lead to root burn and a very weak, unhappy plant come spring. Please, let us rest. We need this quiet period to gather strength for the next growing season.
As we sense the sun strengthening and days lengthening, we slowly begin to stir from our slumber. You will notice tiny new leaves emerging. This is the signal to gently reintroduce nourishment. Begin with a half-strength dose of a balanced fertilizer to avoid shocking our newly active roots. After this first gentle feeding, you can resume the regular every-two-to-four-week schedule with a full-strength solution as we burst into full growth mode once again.
