Adding a small amount of vodka to the water in a vase can help cut flowers stay fresh for longer. Alcohol inhibits the production of ethylene, a plant hormone responsible for the ageing process in plants.
How vodka delays the wilting of flowers
John Dole, a professor of horticulture at North Carolina State University, explained that alcohol works by inhibiting the production of ethylene. This plant hormone is responsible for the ageing process in many cut flowers.
As cut flowers age, visible signs of plant tissue deterioration become apparent. The ethanol contained in vodka interferes with the production of ethylene and thus delays their deterioration.
The correct dilution ratios
Plants can only tolerate low concentrations of alcohol. Vodka with an alcohol content of 40% requires dilution at a ratio of approximately 20 millilitres per litre of water, resulting in a final concentration of approximately 0.8%.
You should not pour vodka directly onto the flowers or fill most of the vase with it. The right amount depends on the size of the vase and the volume of water.
How to apply the method step by step
Before placing the flowers in a vase, prepare the solution according to the specified proportions. This method should be combined with standard care for cut flowers.
It is recommended that you use a clean vase, trim a small section off the stems before placing them in water, and change the water every three days.
Increasing the amount of vodka does not enhance the preservative effect and may impair the bouquet. Plants react negatively to higher concentrations of alcohol, so you should stick to the specified proportions.