Flower Food

    Kids, what’s up with those little cellophane packets of powder that come with cut flowers? They have three components:

    Food:  Sugar is needed to continue development of a bud into a flower, and the flower will perform better in terms of size, color and vase life.

    Hydration:  A wilted flower is one where the cells do not have their full amount of water. The outside ring of the stem is made up of tiny tubes or vessels. This group of vessels transports water from the roots (or vase) to the leaves and flowers. When a flower dehydrates through harvest and shipping, the chemistry needs a jumpstart. Agents that lower the solution pH encourage hydration. This is normally a mild acid such as citric acid.

    Antibacterial:  The water in the vase can quickly become bacteria soup. All it takes is a few stray pieces of plant tissue and some latent bacteria. Bacteria in the water will form plugs in the stem of the flower, blocking the water from flowing through the stem of the flower. The preservative contains an antibacterial agent to stop this from happening.

    Please note:  All chemicals and experiments can entail an element of risk, and no experiments should be performed without proper adult supervision.

    Most packets contain 5 grams and make one pint of solution. Average vases hold at least one quart of water, however. Use too little and there is not enough antibacterial agent and you’ve got a recipe for cloudy, smelly water. The solution is to make your own at home!

    Tulips are a good flower to test plain water versus a preservative (either commercial or homemade). Use the same number of flowers per container, the same size container, and the same volume of liquid. Use warm water (100-110°F or 38-40°C) because it will move into the stems better than cold water. Tap water is fine; in fact the chlorine in tap water acts as a natural disinfectant. Have an adult partner handle the bleach in these recipes:

    Recipe #1

    • 2 cups lemon-lime soda (e.g., Sprite™ or 7-Up™)
    • 1/2 teaspoon household chlorine bleach
    • 2 cups warm water

    Recipe #2

    • 2 tablespoons fresh lemon juice
    • 1 tablespoon sugar
    • 1/2 teaspoon household chlorine bleach
    • 1 quart warm water

    Recipe #3

    • 2 tablespoons white vinegar
    • 2 tablespoons sugar
    • 1/2 teaspoon household chlorine bleach
    • 1 quart warm water

    Which ingredient acts as the food, the hydrating acid, and the antibacterial agent in each recipe?  We have even found websites advocating the use of Listerine™ mouthwash because it contains all of these ingredients! (e.g. <>)


    Kathleen Carrado Gregar, PhD, Argonne National Labs
    March 2008


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