ISSUE 52  |  Best of 2014

Tried and Tested: How to Make Fresh Flowers Last Longer

December 31, 2014 5:00 PM

BY Erin Boyle

We’re not so naive to think cut dahlias will stick around forever, but we’re ready to do what it takes to keep them alive just a little bit longer. What if you dissolve an aspirin in the water? Or drop a copper penny into the bottom of a vase? Can it be that easy?

In the interest of science, we bought a bouquet so we could test five additives people commonly put in water to try to make fresh flowers last longer:

  • Vinegar and sugar mixture. The common wisdom is that vinegar will mitigate bacteria, and sugar will act as food.
  • Conventional flower food.
  • Bleach. The idea is that a teaspoonful will kill bacteria.
  • Aspirin: To increase the acidity of the water
  • A penny: The copper allegedly acts as an antibacterial agent.

Here’s what we learned:

Photographs by Erin Boyle.

Above: Fresh dahlias, straight from the florist.

To begin, we followed best-practice cut flower procedure and coddled our charge with tried and true cut flower care basics:

  • Trim flowers once they’re home; a 45-degree angle is best.
  • Use a clean vase, because the worst enemy of fresh flowers is bacteria. 
  • Keep flowers out of direct sunlight; the cooler and darker the room, the longer your flowers will last.

Above: We ran three sets of trials to try to get the most accurate results, to see if any additive made a cut flower last longer than a dahlia in plain water.

Above: In each trial, we tested sugar and vinegar, bleach, a copper penny, an aspirin tablet, and flower food, courtesy of the corner bodega.

Above: We crushed the aspirin tablet before stirring it into water. 

Above: Marked and measured, I ran each trial for five days. (By that time, all of these fresh-cut dahlias were ready for the compost pile.)


  • Vinegar and Sugar: Flowers strong through Day 3. By Day 5, flowers were curled on the edges and ready for compost, but still relatively intact. Similar results to plain water.
  • Conventional Flower Food: Flowers lasted through Day 3, strong stem through Day 5. In one trial, the flower curled completely by Day 2.
  • Bleach: Strong stem through Day 5. In one trial the flower stayed healthy through Day 4, in another it was shriveled by Day 2. Most inconsistent results.
  • Aspirin: Flower held strong through Day 3 across all three trials, but flopped by Day 5. In each case, the stem turned gray. 
  • Copper: Lasted well through Day 3 in each trial. Stem still strong by Day 5, but flower curled. Similar results to plain water.
  • Water: Flower strong through Day 3, shriveled by Day 4 or 5.


We didn’t see the drastic differences that we thought we might. In our first trial, the bleach and flower food seemed to have actively negative effects on the flowers, but two more trials didn’t prove the same. All things considered, we found fairly consistent results in all three trials, which has us thinking we might just stick to plain water in the future.

But one additive we’ll likely avoid? Aspirin. It turned the stems an icky gray color that was worse than a slightly droopy flower. 

What about you? Do you have a tried and true method? Do you bother with flower food, or let nature run its course?

N.B. This is a rerun of a post that originally published on September 19, 2013 as part of our Modern Root Cellar issue.

See our Floral Arrangements Posts for more flowery inspiration.