Your first strategy for having flower arrangements in your house for the longest possible time is to carefully select the source of those flowers. Flowers should be purchased from a professional floral supplier who has insured that the flowers have been harvested, processed and shipped following all the best practices from the farm to the distributors and finally to you. There are several care and handling best practices, the most important being maintaining a temperature of 33-34 degrees F. Seemingly small delays in shipping, or even being placed on a truck next to a box of flowers that have not been pre-cooled can raise the temperature of the flowers in the subject box several degrees. Those couple of degrees means a couple of days off the vase life of the flowers.
All that being said, other than buying from a reputable, well educated floral distributor, there’s not much you can do to control any of that, so, let’s assume the flowers you’ve received have been treated well from farm to home. Now, what can you do to make the best of an already great thing?
Temperature: Keep your flowers away from heat sources and direct sunlight. Though it is not reasonable to keep flowers cool in the home as a florist would in a cooler, temperature still makes a big difference. Never display your arrangement on a radiator cover, above a heating vent, on a tv or other appliance that gives off heat, or in a window where the sun would heat the space.
Water: Be sure to replenish the water in the container regularly. Flowers that have been processed correctly will continue to transpire throughout their stay in your home. The flowers will need a source of water to keep the stems, foliage and petals turgid and fresh.
Food: On the plant, flowers get their nourishment to develop and grow from the roots and from photosynthesis. Off the plant, this process virtually stops. However, the flower will continue to develop, buds will open and flowers will expand. Some stems will even continue to grow. There is some reserve of sugar or food in the cut flower, but not as much as the flower will need for optimum performance and color. Florists use preservatives in the vase solution to provide this food. When you receive flowers in a box or loose, you should also receive a packet of preservative powder. Follow the mixing instructions on the packet to make a vase solution that will prolong the life of your flowers.
Control Bacteria: The water in the vase or container can quickly become a bacteria soup. All it takes is a few stray pieces of plant tissue and some latent bacteria. Add some sugar from the preservative and you’ve got a recipe for cloudy, smelly water. The problem is not just an aesthetic one. Bacteria in the water will form plugs in the stem of the flower, blocking the water from flowing through the stem of the flower. A good floral preservative contains an antibacterial agent to stop all of this from happening. One caution though. If you do not follow the instructions for mixing the vase solution, and end up making a solution that is too weak, you may be providing enough sugar to grow bacteria while not providing enough antibacterial agents to stop the growth. This is a case where clear water with no preservative would be better than an improperly mixed solution. As soon as you notice that the water in your vase has started to become cloudy, it’s time to dump the water, rinse the stems, give them a clean cut and put them back in the cleaned vase with fresh water. This alone will double the life of your flowers.