From our perspective, the decision to move outdoors is fundamentally governed by soil temperature. Our root systems, the core of our being, remain largely dormant in cold soil. We require consistently warm soil, ideally above 55°F (13°C), to become actively metabolic. When the soil is too cold, our roots are unable to efficiently absorb water and nutrients, leading to stunted growth and a condition you call "transplant shock." Planting us too early, while the ground is still chilled from winter, traps us in a state of suspended animation, making us vulnerable to root rot and other pathogens. The warmth of the soil is not a luxury; it is the signal that awakens our entire physiological process.
Our cellular structure is delicate and highly susceptible to freezing. Ice crystals that form within our tissues during a frost event rupture cell walls, causing irreversible damage. This manifests as blackened, mushy leaves and stems, a fatal injury from which we cannot recover. Therefore, the absolute, non-negotiable prerequisite for planting is the passing of the last average frost date in your local area. This date is a statistical estimate, not a guarantee, but it is the best indicator you have to avoid exposing us to lethal temperatures. Our survival depends on your patience to wait until this threat has conclusively passed.
An abrupt transition from the stable, sheltered environment of a greenhouse or nursery to the harsh realities of the outdoors is immensely stressful. The intensity of direct sunlight can scorch our leaves, and the wind can quickly desiccate our tissues. To thrive, we require a gradual period of adjustment known as hardening off. This process involves placing us outdoors in a shaded, sheltered location for a few hours each day, gradually increasing our exposure to sunlight and breeze over 7 to 10 days. This slow introduction allows us to build thicker cuticles on our leaves and sturdier stems, enabling us to withstand the full force of the elements and establish ourselves more successfully in our new home.
Once the danger of frost is gone and we are properly acclimatized, the combination of longer daylight hours and warmer air temperatures creates the ideal conditions for explosive growth. Ample sunlight is the energy source that fuels our photosynthesis, allowing us to produce the carbohydrates needed to develop new foliage and an abundance of our characteristic trumpet-shaped flowers. The warm air encourages vigorous vegetative growth and promotes budding. Planting us at this optimal moment—when nights are consistently mild and days are sunny and warm—allows us to immediately channel our energy into blooming profusely throughout the entire season, fulfilling our purpose of providing vibrant color.
