If you’re like me, you enjoy wonderful cut flowers from local farmers’ markets. Unlike florists and grocery stores, however, most cut flower growers don’t offer packets of preservative with every sale. Why are preservatives important? They can add days to the life of a bouquet – sometimes even doubling the vase life. If your latest flower purchase doesn’t have that “plant food” packet attached, don’t worry. There are some easy home remedies that work well to make cut flowers last longer.

Clear and cloudy vase water

The vase water on the left is cloudy and needs to be changed. Most commercial preservatives provide clear vase water, as seen on the right.

Photo Credit: Lane Greer

Farmer's market flowers

Who can resist such colorful flower displays? Europeans still purchase more cut flowers than Americans, but with easy access to more flowers at farmers’ markets, that could change.

Photo Credit: Lane Greer

Farmer's market flowers

Beautiful arrangements, such as these with lilies and gladiolus, can be found in most farmers’ markets.

Photo Credit: Lane Greer

A good preservative needs three things: something to lower the pH of tap water (called an acidifier), something to kill bacteria and sugar (yes, plain ol’ table sugar). Commercial preservatives usually contain these ingredients, in varying formulations.

For an acidifier, citric acid is readily available and cheap. It’s present in citrus fruits (like lemons, limes and oranges), but these juices color the vase water. Lemon-lime beverages such as Sprite® and 7-Up® are colorless and contain not only citric acid, but sugar, too (don’t use the diet forms!), so you can kill two birds with one stone. What’s more, you can even use these beverages after they’ve gone flat, since carbonation is not important in maintaining flowers.

To mix, fill half the vase with water and half with Sprite or 7-Up. The only problem with this recipe, though, is that there is no bactericide, and sugar encourages bacterial growth. One way to handle this is to change the vase water often (every other day or so). My colleagues and I tried adding bleach to the mixture, but this wasn’t effective (bleach pushes pH back up).

Adding a lemon-lime beverage to your vase water is probably the easiest way to go. But what about other possibilities? We tested lots of common household items: aspirin, vinegar, bleach, lemon juice – even Listerine® mouthwash! We found that the results depended on the initial pH of the tap water used. In many places, normal pH is around 7.0, and anything that brings pH down is somewhat helpful. So aspirin, small amounts of vinegar and lemon juice were beneficial. In water with naturally lower pH, however, these didn’t work. We had pretty good results using 2 tablespoons lemon juice, 1 tablespoon sugar and ½-tablespoon bleach, but the water turned cloudy. (And don’t use Listerine – it actually killed flowers in two days!)

When you can, get packets of preservative, since they’re specially formulated to make flowers last. But when you can’t, try a simple at-home recipe, and enjoy your flowers longer!