Water and Flower Food
Clean water is essential for keeping cut flowers fresh. Florists use flower food packets that contain three important ingredients: sugar to feed the flowers, citric acid to lower the water pH and help stems absorb water more easily, and a biocide to prevent bacteria and mold from growing in the water. These ingredients work together to keep flowers hydrated and healthy for longer periods.
Stem Preparation
Florists cut flower stems at a 45-degree angle using sharp, clean tools rather than crushing them. This angled cut creates a larger surface area for the stem to absorb water. They also remove all leaves that would sit below the water line in the vase because submerged leaves can rot and introduce bacteria into the water. Some florists re-cut stems every few days to remove any blockages that may have formed.
Temperature and Environment
Keeping flowers in a cool location slows down the aging process and reduces water loss through evaporation. The ideal temperature range is between 65 and 72 degrees Fahrenheit. Florists also keep flowers away from direct sunlight, heating vents, ripening fruits like bananas and apples, and flowers that produce ethylene gas, which causes flowers to wilt and fade more quickly.
Water Maintenance
Fresh, clean water must be changed every two to three days to prevent bacterial growth and maintain proper nutrient levels. Before adding new water, florists rinse the vase thoroughly to remove any bacteria or decaying plant material. Some florists also add a small amount of bleach or flower preservative to the water as an antibacterial agent.
Humidity and Air Circulation
Florists may place flowers in humid environments or mist them lightly to reduce water loss through the petals. However, too much humidity can promote fungal growth, so some air circulation is also important. Keeping flowers away from dry heating systems and air conditioning vents helps maintain the right moisture balance. 
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