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If you kick-start your day with a slug of caffeine, you might consider spraying some on your vegetable garden.

Yes, it’s possible for people to overdose on caffeine, according to the U.S. National Library of Medicine, but scientists say lesser concentrations are lethal to insects, slugs and other interlopers.

A USDA study published in the journal Nature found weak caffeine solutions, sprayed on plant leaves or the dirt around them, either killed or drove off snails and slugs. What’s more, the researchers pointed out, the FDA considers caffeine generally safe for human consumption — unlike molluscicides, which also are toxic to pets, birds, and humans.

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The University of Florida Institute of Food and Agricultural Sciences notes that Caribbean coffee growers separate the caffeine from the bean, potentially creating a new source of slug repellent.

The International Coffee Organization describes four ways to extract caffeine.

The water method involves soaking the beans in water, then soaking up the caffeine using activated charcoal or ethyl acetate, which essentially creates fruit gas.

Another method involves carbon dioxide in either liquid or supercritical (between liquid and gas) state, but it’s expensive and takes up a lot of room. Then there’s dichloromethane, a solvent that you may recognize from the drinking bird but might not care to drink.

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Organic gardeners treasure coffee grounds, not only as compost but also as slug deterrent. But Great Britain’s Royal Horticultural Society warned gardeners in 2012 this practice directly violates European Union regulations against untested home remedies, The Independent reports. After all, as "The World Of Caffeine: The Science and Culture of the World’s Most Popular Drug" notes, a caffeine-producing plant’s leaves and berries accumulate in the soil, eventually “toxic not only to microbial enemies but to the plant itself as well.”

However, you also might want to think twice about caffeinating your personal produce: a more recent study in Australia found caffeine in 91 percent of urban stormwater runoff samples. And in the coffee-drinker’s mecca, the Pacific Northwest, another study found caffeine contaminating Oregon’s coastal waters.

With drought, middlemen and expected shortages driving up coffee prices, perhaps a saucer of flat beer for Sluggo is the better part of valor.

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'Morning Dew' (David Chambon)