For all you budding scientists wanting to experiment with different types of floral preservatives, here is some help with setting up your experiment.

Flowers have a pre-set or pre-determined life that is established by the plant (or its genetics). Some flowers last a day while others may last up to several months (on the plant). Scientists have not unlocked the secret to flower life, but have some insight. What you want to experiment with is how long humans can keep flowers alive once they are removed from the plant. It is interesting that even our best efforts don't often exceed the life nature has "programmed" the flowers to have. With proper care, however, some flowers will last up to a few weeks.

The plant provides flowers with a food source and water. That's what you're trying to provide in the vase in a form useful to the flower. Some substances have a food source (sugar) that may help the flower live a bit longer. Water is supplied in the vase (obviously, where the substances are dissolved). However, the sugar alone in the vase will promote the growth of bacteria and fungi, clogging the xylem (part of the stem that takes up water). So, an ideal floral preservative has a balance of sugar and an acid (to deter the bacteria and fungi from growing) to extend post-harvest life the most.

Here is a good experiment to begin with. Find several (3-9) identical glass or plastic containers (vases or glasses will work just fine). Do not use metal containers as they will sometimes react with the things you put into solution in the vase. Next, find several identical flowers. I like to use carnations for this experiment (standard white) since you can see them brown and they do last for several days. Chrysanthemums will work well, too, as will mini carnations. I suggest you use 3 flowers per vase as you will see some variation in the flowers in one vase.

Next, determine your treatments. Into each vase or container, add the same amount (8 to 12 ounces) of warm water. Using warm water helps to dissolve the items you add and warm water is best to restart the uptake of water into the stem. Into the first vase or glass, dissolve a teaspoon of sugar. In another vase or glass, dissolved a packet of commercial floral food (the flower preservative sold at most florists and supermarket floral departments). Use a third vase as your control (water only). In the other vases or treatments, you might try grinding an aspirin into powder, adding a penny, adding one teaspoon of bleach, or 4 oz. of citric soda. You could try many things, but don't mix chemicals and have appropriate supervision when you are creating your treatments.

Take readings daily. Perhaps you could rate the freshness of the flower, the cloudiness of the vase (why is it cloudy, you ask? Bacteria and fungi are growing!). You might take pH readings daily if you have that equipment. My hypothesis is that the commercial flower food will last longest, followed by water, then the sugar & water mixture, then any other treatments. Let me know how yours turns out.

Keep enjoying science - the world needs more scientists!

- Bridget

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