Do copper coins prolong the life of flowers?

Dr Jo Buckley presents the next Hit of Myth challenge!

Have you noticed that fresh cut flowers don’t seem to stay fresh for very long? So can you prolong the life of flowers using chemistry?

The Chemistry

Cut flowers begin to degrade almost instantly. Air and bacteria can block the small pores of the vascular system of plants, stopping vital water and food from being distributed around the flower, and they start to wilt.

Historically, certain metals were noted for their ability to reduce bacterial growth. Two and a half thousand years ago, vessels made from copper and silver were discovered to keep food and drink bacteria-free for longer.

Fast forward a couple of thousand years and you can buy plasters to apparently help your cuts heal faster, pyjamas rumoured to stop you from contracting bacterial infections and socks alleged to help those afflicted with smelly feet – all impregnated with antimicrobial metals.

Metals such as copper, silver and gold are toxic to bacteria because the metal binds to enzymes responsible for respiration, deactivating them and killing the bacteria.

So if we can slow the rate of bacteria forming in the water by adding an antimicrobial metal, will our flowers last longer?

The Experiment

  1. Find yourself a copper coin (e.g a UK  two pence piece or US one cent).
  2. Clean it using toothpaste, to remove any unwanted dirt and leave the toothpaste on the coin whilst you do this next bit.
  3. Cut the flowers’ stems at a 45 degree angle to maximise the water uptake. Put them into two identical vases, drinking water glasses or jam jars, each filled with an inch of water. Over the course of the experiment, try and keep this water level constant.
  4. Next, rinse the toothpaste off your coin and drop it in one of the vases. Your other vase will be your control.
  5. Leave the flowers in a light place where they won’t get disturbed.
  6. Record which vase of flowers looks fresher over 1, 3, 5, 7 and 10 days, or whether they both look the same.
  7. Tell us your results using this simple online survey.

By taking part, your results will help determine whether adding a copper coin to prolong the life of fresh cut flowers is a hit or a myth.


2 comments on “Do copper coins prolong the life of flowers?”

  1. David BattsonReply

    Do copper coins prolong the life of cut flowers? The best way to make cut flowers last a long time is cut back the stem every 2 to 3 days this then allows the water/nutrient to be taken up by the flowers.

  2. Stephanie MitchelReply

    Infact copper coins can’t help to the flowers. The release rate of copper is very slow, so this method is totally ineffective. And one more thing – the UK & US copper coins no longer contain copper but a copper coloured steel alloy, so there’s no releas at all.

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