Cut flowers have a longer vase life when some type of flower food is added to the water. The main ingredients in flower food are carbohydrates, biocides and acidifiers. While the exact ingredients of commercial flower food are secret, many homemade solutions include sugar, bleach and lemon juice.
Once cut flowers are removed from their major food source (the plant), they need carbohydrates for nutrition. Sugar or sucrose provides the energy that cut flowers need for energy and cell metabolism, so buds will continue to open.
Bacteria, fungi and yeast feed on the sap from the stems of cut flowers and clog the water transport tubes in the stems. Biocides, such as bleach or the antibacterial ingredient in mouthwash, inhibits their growth and provides a healthier environment for the cut flowers.
Most water is alkaline, which reduces the life of cut flowers. An acidifier, such as citric acid, adjusts the pH of the water and helps the stems take up water and nutrients. Acidifiers also stabilize the color of the flowers.
Homemade Flower Food
Make flower foods with ingredients found in the home. Sugar is a carbohydrate, bleach is an antibacterial cleanser and lemon juice contains citric acid.
Lemon-lime soda (not diet) contains sucrose and citric acid. Mouthwash is acidic, and contains sucrose and an antibacterial ingredient.