April 19, 2006

Prof: Alcohol Helps Control Plant Growth

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The next social drinker you might invite to your apartment won’t get your neighbors calling the cops on you – in fact, they might just have one of their own at home. That’s because instead of partying loudly when they get drunk, paperwhite daffodils, a common house flower, just stop drooping, according to research published in this month’s HortTechnology magazine.

The article, co-authored by Prof. William Miller Ph.D ’86, horticulture, and Erin Finan ’05, finds that watering the plans with a solution of four to five percent alcohol stunts paperwhites’ stem growth without affecting their flower size or fragrance.

Paperwhites are “fun to grow, they’re fragrant, and they’re nice,” Miller said.

But left to their own devices, the flowers soon lose their charm.

“They grow tall, and they fall over, and they’re just aesthetically garbage when they do that,” Miller said.

Miller and Finan first experimented growing paperwhites with plain ethanol, but once those flowers turned out well, the two turned to more readily available sources.

“It was not then a great leap of logic to go down to Northside and to buy a supply of various alcohols,” Miller said.

The hard liquor – gin, vodka, whiskey, rum, tequila and peppermint schnapps – produced plants that were normal in all but height, but when the plants were given wine or beer, “they were effectively dead,” he said.

Miller said that ingredients such as tannins and acids in red or white wines could be responsible for killing the flowers. With beer, the suspected culprit was the drink’s sugar content – and the microbes it invites.

“Sugar also allows fungi to grow and bacteria to grow,” he said. “Heineken’s four-and-a-half percent alcohol … you’d be adding one ounce of water to a 12 ounce bottle of Heineken to get four percent alcohol, so you’re effectively talking about pure Heineken. And if you soak anything in pure Heineken for a week, it’s going to be pretty nasty.”

Although the experiments were conducted with brand-name liquors, Miller said he presumes that the cheap stuff should work just as well.

Like anything else in life, and especially when alcohol is involved, moderation is best for paperwhites. At about four to five percent, the flowers grow short yet strong. Raise that amount to 10 percent, though, and the plants start to suffer. At about 25 percent, they die.

According to the researchers, paperwhites should start out with plain water. About a week after planting, once their roots are growing and the shoot is green and about one or two inches tall, the grower should pour off the plain water and start the alcohol mix.

Although research hasn’t confirmed it yet, Miller said one theory behind the alcohol’s effect is “water stress” – essentially, diluting the actual water in the solution so that the plant stays thirsty. Greenhouse growers have used water deprivation – “wilting” – to keep plants short for a long time, Miller said, but that can be dangerous if people try it at home.

“A little bit of wilt becomes a lot of wilt. You’re working that day, and if your plant starts wilting at 9 in the morning and you don’t get home till 6 or 7, then you have a problem,” he said. “If the plant wilts too much, then it dies.”

Miller first got the idea for the experiment when a New York Times reporter asked him to verify a theory that pouring gin on paperwhites would keep them short due to juniper’s “essential oils.” Skeptical that oil had much to do with it, Miller instead turned to the alcohol content and proposed the experiment to Finan as a senior project.

“It was kind of interesting because nobody had ever done substantial research on the effect of alcohol on plants,” Finan said. And although she expected the alcohol to just kill the flowers outright, the results were nearly perfect.

“It was great, because the flowers actually responded exponentially in growth” to the proportion of alcohol, she said.

The flower-growing industry already has various methods of controlling plants’ heights, such as chemical treatments or environment regulation, but Miller said that this research is the first to give that level of control to the everyman.

“[I]t is very typical for the homeowner to buy these plants, plant them up, they get too tall, and just when they’re about ready to get nice – they flop over. … It would be much nicer just to use this alcohol method.”

With paperwhites under his belt, Miller is now starting to move into the realm of vegetables. There, even commercial growers who want to sell, for instance, tomato plants to gardeners have trouble, since chemicals are banned on the edible products. Growers can stunt growth by physically touching the tomatoes – the plant senses the touch and slows its growth – but that can be impractical for large nurseries.

As for Finan, she said she hasn’t used the technique at her job gardening a private estate north of New York City, but she did use it to grow some paperwhites for her parents last Christmas. And though she said she doesn’t believe the technique will work on plants other than bulb flowers, she said she’s looking forward to the results, admitting that she was already wrong about plants and alcohol once before.

Many of the local florists The Sun contacted had not heard of the technique, and none had tried it yet, since paperwhites are mostly grown in winter. Holly Nash, who is the manager of Flower Fashions By Haring on Hanshaw Road, said she would want to try it herself before advising her customers of the technique.

“I might try it at home next winter,” she said. “Intoxictaed plants are a whole new thing for me.”

Meanwhile, Miller and Finan are enjoying the publicity the experiment has garnered. News of the research has been published internationally, and the experiments have been mentioned on several television and radio shows.

“I think the reason it has so much publicity is that it’s practical to gardeners,” Finan said. “I’ve heard a lot of people trying it out.”

Archived article by Yuval Shavit
Sun Senior Writer