A household refrigerator can temporarily extend the freshness of cut flowers. This method is ideal for holding blooms overnight or for a day or two before an event, not for long-term storage. Controlled cold storage pauses the aging process, helping maintain the flowers’ vibrant appearance and structural integrity. Successfully using this technique requires understanding the science of temperature change and following specific steps to prevent dehydration and damage.
How Cold Temperatures Preserve Flowers
The mechanism behind preserving flowers with cold temperatures relates directly to the plant’s metabolism. Cut flowers continue to respire, breaking down stored carbohydrates to produce energy, carbon dioxide, and water. This energy expenditure depletes the flower’s limited sugar reserves, accelerating wilting and senescence (natural aging).
Lowering the temperature significantly slows this respiratory rate, essentially putting the flower in a state of suspended animation. By reducing the speed at which the flower uses its internal energy stores, the cold environment delays the time until the flower runs out of fuel and begins to collapse. The ideal temperature range for most non-tropical cut flowers is between 33°F and 40°F (1°C to 4.5°C). This range is cold enough to slow metabolism without causing freezing damage to delicate tissues.
A Step-by-Step Guide to Fridge Storage
To prepare flowers for temporary storage, first ensure they are well-hydrated. Re-cut the stems at an angle using sharp shears or a knife to maximize the surface area for water uptake. Immediately place the trimmed stems into a clean vase filled with cool water, adding a flower food packet if available.
A household refrigerator has low humidity, which can cause rapid dehydration, unlike commercial floral coolers. To counteract this drying environment, gently mist the flower heads with water before storage. Then, loosely cover the entire bouquet with a barrier like damp newspaper or parchment paper to create a localized pocket of high humidity around the blooms.
Adjust the refrigerator’s temperature to approximately 40°F (4.5°C) to approach the ideal range while maintaining a safe margin above freezing. Place the prepared flowers on a shelf where they are upright and avoid contact with the sides or back of the appliance. The vegetable crisper drawer can be a suitable place, provided it is completely cleaned out and free of any other contents.
Avoiding Common Hazards When Refrigerating
The most significant threat to flowers in a household refrigerator is ethylene, a colorless, odorless gaseous plant hormone. This gas is naturally produced by some plants to regulate ripening and aging. Even minute external exposure can cause rapid deterioration in cut flowers, leading to accelerated wilting, yellowing of leaves, and premature petal drop.
The primary source of ethylene in a kitchen setting is ripening produce. It is necessary to remove all fruits and vegetables, especially high-emitters like apples, bananas, and tomatoes, from the refrigerator when storing flowers. Flowers are sensitive to concentrations as low as 0.1 parts per million, making separation from all produce mandatory.
You must also guard against temperature extremes within the appliance. Home fridge temperature control can be inconsistent, leading to cold spots near the cooling element or along the back wall that can freeze the blooms and cause irreparable damage. Standard refrigeration temperatures will also cause chilling injury to tropical flower varieties, such as orchids, ginger, and birds-of-paradise, which require a warmer environment above 50°F (10°C).