Is that stuff of any value? I’ve heard mixed reports, although it seems reasonable that with all the research that is done in the flower growing industry, those little packets would contain something that would extend the life of the flowers they’re sold with. What is it? Does it work? How?
Yes, for the most part the floral preservatives do act to extend the life of flowers. In general, they do this by containing three key ingredients: 1) some form of sugar to supply energy to the flower, 2) a bacteriocide to kill off nasties which break down tissue and decrease water uptake and 3) an acidifier to lower the pH which further helps to retard bacterial growth.
Cite–(PDF doc).