Flowers like carbs and a clean house.
Straight up: Flower food can prolong the life of your vase arrangements by 50%. BUT you don’t really need to use it if you are a champ at keeping your water fresh and containers clean. I am diligent about keeping my water clean and tend to begin adding a bit of food to my vases after the cut flowers are about a week old, just to give my blooms a boost in their final days.
I go this route because flower food serves four major functions:
It provides sugar (carbohydrates)
It serves as a germicide to keep the ickies out
Its acidity promotes water uptake
It does something else sciency that controls plant growth
You can make it easy on yourself and buy flower food online. Two of the major brands are Chrysal and Floralife. If you use too much, things can go south, so take it easy.
You can also make your own mix at home. Weirdly, according to the Association of Speciality Cut Flower Growers, the best option is a 50/50 mix of classic lemon-lime soda with real sugar. It contains sugar, an acidifier (citric acid), and a germicide.
Option 2, according to Clare Nolan, author of the very lovely In Bloom, is to mix 1 tsp sugar (carbs), 1 tsp bleach (germicide), 2 tsp of vinegar (acidifier) and 2 pints of tepid water in a little jar. Add a few ounces to your (clean!) vase water.
