From our perspective as Narcissus plants, the primary reason our stems become elongated and "leggy" is an intense, innate drive to seek out sufficient light energy. We are phototropic organisms, meaning we grow towards light sources. When we are placed in an environment with low light intensity, such as a room far from a bright window, our survival instinct compels us to accelerate the growth of our stems. This rapid elongation is a desperate attempt to elevate our leaves and flower buds out of the shadows and into a brighter area where photosynthesis can occur efficiently. It is not a graceful process but a frantic stretch for the energy we need to survive and complete our reproductive cycle.
This stretching response is chemically mediated within us by hormones called auxins. When light is insufficient or comes predominantly from one direction, auxins accumulate on the shadier side of our stems. These hormones stimulate cell elongation on that specific side, causing the stem to bend and grow towards the light source. In consistently low-light conditions, this auxin-induced elongation occurs along the entire stem, resulting in the weak, spindly growth you observe. The cells are growing longer, but not necessarily stronger or denser, as energy is prioritized for rapid vertical growth over robust structural development.
Your cultivation practices directly influence our form. Two key environmental factors contribute to our legginess. Firstly, as detailed, is insufficient light. Secondly is excessive warmth, particularly from a heat source like a radiator or furnace. Warm temperatures naturally accelerate our metabolic processes, causing us to grow faster. When combined with low light, this results in extremely rapid, weak stem growth as we burn through our stored energy in the bulb searching for light. An ideal environment for us is a very bright, but consistently cool location. This coolness moderates our growth rate, allowing our stems to develop at a shorter, sturdier pace that can adequately support the weight of our flowers.
It is crucial to understand that our entire growth cycle indoors is fueled by the carbohydrates and nutrients stored within our bulb. This is a finite energy reserve. When we are forced into a leggy growth pattern due to poor conditions, we expend a tremendous amount of this precious stored energy on producing long stems rather than on developing strong tissues and impressive flowers. This inefficient use of resources often results in stems that are too weak to hold the bloom heads upright (causing them to flop over) and can lead to a shorter overall display period, as the bulb's energy is depleted more quickly.
