Florists employ a blend of scientific principles and precise handling techniques to maximize the longevity of cut flowers, moving them from harvest to display with minimal degradation. The core strategy is to significantly slow the natural aging process while preventing the growth of microorganisms that cause premature wilting.
The Science of Cold Storage
Temperature regulation is one of the most effective methods florists use to extend the life of a bloom. Most cut flowers are stored in specialized walk-in coolers set to a range of 33°F to 35°F, which is just above freezing. This low-temperature environment dramatically reduces the flower’s metabolic rate and slows down the process of respiration, preserving the quality of the petals and foliage for a longer period.
The refrigeration unit also maintains a high level of humidity, ideally between 90% and 95%. This high moisture content helps to prevent dehydration, a common cause of wilting in cut flowers, by reducing the rate of water loss through transpiration. However, not all blooms tolerate this chill; tropical flowers, such as anthurium and orchids, are considered cold-sensitive and require warmer storage temperatures, typically around 50°F to 55°F, to prevent chilling injury. Maintaining a consistent temperature within the correct range is paramount, as fluctuations can stress the flowers and encourage condensation, which promotes fungal growth.
The Role of Floral Preservative
The water flowers drink is not just plain H₂O; it is a carefully formulated nutritional solution known as floral preservative or flower food. The first component is a carbohydrate source, typically sugar, which acts as energy to fuel the flower’s continued metabolic activities, like maintaining cell structure and color. This sugar replaces the natural food source the flower lost when it was cut from the parent plant.
The preservative also includes an acidifier, such as citric acid, which is designed to lower the water’s pH level to a slightly acidic range, often between 3.5 and 5.0. This acidity mimics the natural pH of the flower’s cell sap and significantly improves the flower’s ability to absorb water through its stem. The third component is a biocide, an antibacterial agent like a chlorine compound or silver thiosulfate, which is added to inhibit the growth of bacteria, yeasts, and fungi in the vase water. Without this biocide, microorganisms multiply rapidly, forming a slime that clogs the flower’s vascular system, preventing water from reaching the bloom.
Precision Stem Preparation
The way a stem is cut directly influences the flower’s ability to hydrate and is a fundamental technique in floristry. Florists use sharp, sanitized tools, such as floral shears or a clean knife, to make a fresh cut, typically removing at least a half-inch to an inch of the stem. A sharp tool ensures a clean severance, avoiding the crushing of water-conducting tissues that can occur with dull scissors.
The cut is made at a 45-degree angle, which achieves two important outcomes for the flower’s health. Cutting at an angle maximizes the surface area of the stem’s opening, allowing for greater water uptake. It also prevents the stem from resting flat against the bottom of the container, which would seal off the vascular tissue and block the flow of water. To further ensure uninterrupted hydration, some sensitive flowers are re-cut while the stem end is fully submerged underwater, a process that prevents air bubbles, or embolisms, from entering the xylem vessels and creating a blockage.
Conditioning and Handling
Before flowers are placed in their final display container, they undergo a crucial process of initial hydration and conditioning. Upon arrival, all foliage that would fall below the waterline is meticulously stripped from the stems. This step is necessary because submerged leaves quickly decay, releasing bacteria and organic matter into the water that can contaminate the solution and contribute to stem clogging.
The initial hydration phase involves placing the freshly cut and cleaned stems into a solution of warm water mixed with floral preservative. Warm water, often between 100°F and 110°F, is used because its molecules are smaller and move more quickly, allowing for water absorption by the newly cut stems. Florists allow the flowers to “drink” and fully rehydrate for a period, often two to four hours, or even overnight, before they are arranged or sold. This conditioning ensures the blooms are turgid and fully saturated with water and nutrients.
Florists also practice careful environmental management by keeping flowers away from ripening fruit, such as apples or bananas. These fruits naturally release ethylene gas, a plant hormone that signals maturity and senescence, or aging, in the flowers. Exposure to this gas can accelerate the flower’s decline, leading to premature petal drop and wilting.