Cut flowers can generally be stored in a refrigerator, but success requires proper preparation and careful environmental management. Florists use refrigeration to temporarily pause the natural aging process of blooms. This cold storage significantly extends the vase life of flowers by reducing the speed at which they naturally deteriorate. When done correctly, placing flowers in a cool, dark space preserves their freshness until they are ready for display.
The Science Behind Cold Storage
Cooling flowers slows down their biological processes, primarily by reducing the rate of respiration. Respiration is the cellular process converting stored sugars into energy, which fuels the flower’s life cycle and decline. Lowering the temperature decreases the flower’s metabolic rate, meaning it consumes stored energy reserves much slower. This metabolic slowdown puts the flower into a temporary state of dormancy, preserving its structure and delaying senescence.
Another benefit of refrigeration is the reduction of water loss, known as transpiration. Transpiration is the evaporation of water from the flower’s leaves and petals, accelerated by warmer temperatures and dry air. A cooler environment naturally lowers the vapor pressure deficit between the flower tissue and the surrounding air. This helps the petals and stems retain water, maintaining turgidity and preventing wilting.
Essential Steps for Safe Refrigeration
Proper preparation of the stems is necessary before cold storage to ensure optimal water uptake later. Stems should be trimmed at a sharp angle using a clean, sharp instrument to maximize the surface area for hydration. This initial cut is important because air bubbles can form and block the vascular system if the stems are not immediately placed into water.
It is also important to remove any foliage that would sit below the water line when the flowers are eventually placed in a vase. Submerged leaves quickly decay and introduce bacteria, which clogs the stems and accelerates aging. While in storage, the flowers must be placed in fresh water or a specialized floral hydration solution to ensure they remain fully turgid.
Because household refrigerators are typically dry, flowers must be loosely wrapped before cooling. Wrapping them in newspaper or placing them inside a ventilated plastic bag creates a localized high-humidity microclimate around the blooms. This protective barrier minimizes the drying effects of the cold, circulating air.
The temperature inside the refrigerator must be carefully monitored to provide benefit without causing damage. The ideal range for most cut flowers is between 38°F and 45°F (3°C to 7°C). Maintaining this cool, stable temperature slows metabolic processes without subjecting delicate tissues to harmful cold stress.
Hidden Dangers in the Refrigerator
Despite the benefits of cold storage, the common household refrigerator presents two specific threats that can quickly negate any preservation efforts. The most significant hidden danger comes from ripening fruits and vegetables stored alongside the flowers. These items, particularly apples, bananas, and tomatoes, naturally release the gaseous plant hormone known as ethylene.
Ethylene gas promotes senescence, or biological aging, even in minute concentrations. Exposure to this hormone accelerates wilting, petal drop, and browning in most flower varieties. Florists use dedicated, produce-free refrigeration units, and home users must keep flowers far away from any gas-producing food items.
The second major threat involves temperature control, specifically the risk of accidental freezing or chilling injury. Placing flowers too close to the freezer compartment or a cold air vent can cause localized temperature drops below freezing. Ice crystals forming within the plant cells rupture the cell walls, leading to immediate and irreversible tissue damage.
Temperatures above freezing but below the optimum range can cause chilling injury in sensitive tropical or subtropical species. This damage is a physiological breakdown, not immediate cell rupture, resulting in water-soaked spots, browning, or a failure to open properly. It is important to ensure the refrigerator setting does not dip below the lower recommended limit of 38°F to protect the cellular integrity of the blooms.