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The Latest Dirt - March 2023

What is the Effect of Pouring Alcohol Into the Yard

By Terry Lippert

Client’s question:
Can you tell me anything about pouring out old alcohol into the yard/garden/dirt?
We have some cases of wine, champagne, & spirits.

Terry Lippert’s reply:
Thank you for contacting our UC Master Gardener Help Desk. You’ve asked about the effect of pouring out old alcoholic beverages (wine, champagne, and spirits) into the yard and garden. We do not recommend disposing of alcohol in this manner. It would likely kill or significantly harm your plants.

Roots Damaged by Alcohol. https://journals.ashs.org/horttech/view/journals/horttech/16/2/article-p294.xml
Roots Damaged by Alcohol. https://journals.ashs.org/horttech/view/journals/horttech/16/2/article-p294.xml

My research located a scientific journal article published by the American Society for Horticultural Science reporting on a study of the effects of growing paperwhite narcissus bulbs with a water/ethanol mixture. (Ethanol is the type of alcohol in spirits, wine, and beer.) The study’s authors (a Cornell University Ph.D. and a Cornell grad student) conducted the study to test whether there was any validity to an “old wife’s tale” saying that the alcohol would limit the tall growth that causes the plants to fall over after blooming. Interestingly, the study results did show that using a 4% ethanol mixture to grow the plants did result in plants that bloomed well without growing tall enough to fall over. In other words, it acted as a growth retardant for the plants without harming the desirable blooms.

When a greater than 4% ethanol mixture was used, it severely stressed the plants. When the ethanol percentage was 10% or greater, the effect was toxic leading to the death of the plants.

After using lab ethanol initially, the study’s authors experimented with substituting hard liquors (e.g., gin and vodka), wine, and beer. Even when diluted to 4%, beer and wine (both red and white) killed the plants. As long as the hard liquors were diluted to the 4% level, they also stunted the tall growth of the paperwhites without harming the desirable blooms.

So, in theory you might be able to dispose of old spirits in the garden without killing the plants so long as you diluted the spirits to the 4% level. That dilution would require lots of water since many spirits contain 40% or more alcohol. And even with that heavy dilution of water, you would likely at least stunt the growth of your plants. And the fact that the paperwhite narcissus used in the Cornell study bloomed well despite the use of 4% ethanol doesn’t mean that other plants would respond in that manner. Also, as the results of the study showed even if the wine were heavily diluted with water, it would still likely kill your plants.

You can read the full study referenced above at this website: https://journals.ashs.org/horttech/view/journals/horttech/16/2/article-p294.xml

To find suggestions for disposing of old liquor, try doing an internet search “how to dispose of old liquor”. I hope that this information is useful.