Flower Food for Cut Flowers: What Works, What Doesn't
Aspirin, coin, sugar, vodka — household hacks tested with honest results.
Every grandmother has a tip for keeping cut flowers fresh. Some are correct, most are myth. Here's an evidence-based overview.
What works scientifically: the flower food sachet from your florist. Contents: 1) sucrose / sugar (energy for the bloom), 2) biocide (e.g. NaDCC, kills bacteria in water), 3) pH buffer (citric acid, optimises water uptake). Studies show 25–50% longer vase life.
What partly works: 1 teaspoon sugar plus 1 tablespoon vinegar per litre water. Sugar = energy, vinegar = mild biocide + pH lowering. Substitute for flower food, weaker. Beats nothing.
Bleach myth: a drop of chlorine bleach per litre water is biocidal and slows bacterial growth. Actually works, but: must be exactly dosed or it damages the plant. We don't recommend for consumers.
Aspirin: in most studies NO measurable effect. Some claim the salicylate effect adjusts pH similar to flower food — but concentration in a vase is too low.
Coin (copper): theoretically effective (copper is biocidal), in practice only with real copper coins (old 2-pfennig pieces). Modern cents are copper-plated — ineffective. Not recommended.
Vodka / gin: contains ethanol, biocidal in low concentration. 1 drop per litre is theoretically fine, but florists see no practical advantage over flower food.
Cola: the myth-of-choice. Effect: sugar (good) plus acid (good) plus caramel colorant (bad — feeds bacteria). Not recommended.
Sugar-free soda (Zero / Light): worthless — no energy (sugar-free), the acid isn't plant-targeted.
Salt: harmful to most cut flowers. Definitely not.
Pure care without additives: regular water change (every 2–3 days), angled stem cut, strip lower leaves — gives 80% of the effect. Flower food adds the last 20%.
Frequently asked
- Can I buy flower food if the sachet is empty?
- Yes — available at any florist, about €0.50 per sachet. Enough for about 0.5 L of water. For large bouquets use multiple sachets.
- How often should I add flower food?
- With every complete water change (every 2–3 days). Don't 'top up' without full water change — concentration becomes wrong.
- Are expensive flower foods better?
- Marginally. Standard florist food (e.g. Chrysal, Floralife) all work similarly. Premium versions cost €2–3, deliver little additional benefit.