Cut flowers in the compost – yes please!

The fact that Valentine’s day was only a few days ago reminds me of a question that came from community member Jody in Watson: are cut flowers ok in the compost heap? This turned out to be quite the thought provoking question so thanks for asking it Jody 🙂 Specifically, Jody was wondering about the preservatives that are added to vases to prolong the life of cut flowers as someone had mentioned that these are perhaps best kept out of the compost heap and away from the diverse ecology that the heap harbours.

This was not a consideration that had occurred to me before but even before I looked into just what the ingredients of flower preservatives are I guessed that the answer would be: “nah, she’ll be right!”. This is what I wrote back to Jody initially:

“The cut flowers are a great question. Myself and others have definitely added some to the heap and I haven’t thought there would be any problems with this. I will look into the preservatives question. I suspect there is no concern necessary, due to not only the dilution of these chemicals in the larger volume of the heap but also due to some ‘bioremediation’ activity. The compost heap is a bioreactor and a very complex one at that. This complexity leads to some amazing phenomena such as the ability to detoxify some of the chemicals that we don’t want hanging around in our environment. It’s really cool stuff 🙂 Of course without fancy scientific equipment I can’t be sure which reactions are occurring but I can make some educated guesses.”

This is the kind of science that I love pondering and learning more about so if anyone has any similar questions then ask away!

In the end cut flower preservatives turn out to be quite simple. Whether you make up your own solution or use the sachets provided by a florist it’s basically a small amount of a simple acid, a little sugar and a tiny bit of bleach [source]. Any sugar left on the flowers will be beneficial for the heap (everyone loves sugar, animal, insect, bacteria or fungi, in moderation of course). The heap generates its own acids and a tiny bit more won’t hurt. As for the bleach, any trace amounts may indeed kill a bacterial/fungal cell or two but the community will not be dinted. So please do add cut flowers to your buckets. They will certainly add a smile to my face, making me think that someone has been romantic to someone else or that someone was enjoying a lovely spot of self-care 🙂 If they are flowers with scent then all the better! The compost benefits from balancing nice odours with the occasional unpleasant one. Unfortunately though, those scents are not only absorbed quite quickly into the millieu and nullified but they can also be transformed with the bioremediation/biotransformation reactions mentioned above.

Anyway, more on all that another time. For now, enjoy this pic of the best cut flowers of all, exuberant dahlias.


destiny = compost

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