You can keep flowers in the refrigerator to extend their freshness. Refrigeration provides a controlled, cool environment that temporarily slows the biological processes of cut flowers. When done correctly, temporary cold storage can pause the aging process, allowing blooms to maintain their vibrant appearance and structural integrity for a longer period. This method serves as an effective way to preserve a bouquet for an overnight period or for a day or two before an event.
How Cold Temperatures Affect Flower Longevity
Cold storage works on the principle of slowing down a cut flower’s metabolism, which is still active even after being harvested. Flowers, like all living organisms, continue to respire, consuming their finite energy reserves stored as sugars in their tissues. Lowering the temperature significantly reduces this rate of respiration, essentially putting the aging process on pause.
The optimal temperature range for most cut flowers is between 34 and 38 degrees Fahrenheit. Maintaining this temperature conserves the flower’s food supply and minimizes the rate of water loss, or transpiration, keeping the flowers crisp and hydrated. Tropical flowers are an exception, as they require warmer storage, usually around 50 degrees Fahrenheit, to prevent chilling injury.
The Dangers of Ethylene Gas and Freezing
The home refrigerator presents two primary threats to cut flowers: ethylene gas and freezing temperatures. Ethylene is a colorless and odorless gaseous plant hormone that promotes ripening in fruit and aging (senescence) in flowers. Fruits and vegetables, such as apples, bananas, and avocados, are high emitters of ethylene and should never be stored near flowers. Exposure to this gas can cause premature wilting, petal drop, bud failure to open, and yellowing of the leaves in sensitive flowers like roses and carnations.
Additionally, the temperature within a home refrigerator is not always uniform. Placing flowers too close to a freezer compartment or a cold air vent can be disastrous. Temperatures at or below 32 degrees Fahrenheit cause the water inside the plant cells to freeze, forming ice crystals that rupture the cell walls. This freeze damage results in wilted, discolored, and mushy blooms that have lost their structural integrity.
Safe Preparation and Storage Steps
Successfully storing flowers in a refrigerator requires careful preparation to mitigate the risks associated with the home environment. Begin by ensuring the flowers are well-hydrated; trim the stems at an angle using a sharp tool and place them in fresh, cool water for at least 30 minutes before refrigeration. Remove any foliage that would sit below the waterline to prevent bacterial growth, and remove any damaged leaves or blooms, as decaying matter also emits ethylene.
The blooms should be protected from the dry air and food contaminants inside the fridge. Wrap the flower heads loosely in several layers of newspaper or a plastic bag to create a humid microclimate and shield them from drafts. Clear out all fruits and vegetables from the section where the flowers will be placed to prevent ethylene exposure. Finally, place the wrapped flowers horizontally or upright in a designated, clean area, away from the back or sides of the fridge where temperatures are more likely to drop below freezing.