Coffee as a barrier and as a spray for snails and other pests:

Caffeine can repel or kill snails that might otherwise eat and ruin plants. Coffee which is an environmentally acceptable, natural compound, has great potential as an alternative to today’s snail- and slug-killing chemicals. That’s according to Robert G. Hollingsworth, a research biologist with the agency’s U.S. Pacific Basin Agricultural Research Center in Hilo, Hawaii.

Hollingsworth conducted caffeine studies in collaboration with research entomologist John W. Armstrong at the Hilo Center and Earl Campbell of the U.S. Fish and Wildlife Service, Honolulu.

The idea of using caffeine to quell pests isn’t new. But Hollingsworth and colleagues apparently are the first to report its prowess in clobbering pesky molluscs such as Hawaii’s orchid snail, Zonitoides arboreus. The tiny snail is a common and costly pest to growers of Hawaii’s colorful and exotic tropical orchids.

In preliminary experiments at his research greenhouse in Hilo, Hollingsworth applied a 2 percent solution of caffeine in water as a spray to the coconut husk-chips material in which orchids are grown. This growth medium, called coir, was infested with the tiny snails. The scientists found that the caffeine spray killed up to 95 percent of the snails.

In another experiment, the researchers showed that growth medium treated with the 2 percent caffeine solution had only 5 snails, when checked 30 days after the spray was applied. That’s in contrast to the 35 snails that they found in growth medium that had been treated with a standard dose of metaldehyde, a common molluscicide.

Caffeine, a naturally occurring compound in coffee and chocolate, for example, is ranked “generally recognized as safe” by the Federal government.

As a Barrier

Apply a thin layer and turn into soil.

Apply once a month for roses and other plants.

Add to garden soil before you plant.

no more snails! No more pests! That easy...

As A Spray

Normally, when I am making a batch of coffee to be sprayed, I am usualy spraying coffee to help raise the Brix of the plant in question. But for making a spray of coffee that will be used to reduce snails and slugs, it is best to use the coffee at full strength. In this case, I would buy the cheapest organic coffee I can find and make a gallon of coffee the way you normally would make coffee. Yu may have to make a few batches in order to get a gallons worth. Another simple method is to get a bucket, put a gallon of water into it. Then Pour into the water a cup of coffee grounds. I woud put the coffee grounds into a panty hose and tie up into a ball, making a "tea" bag. Let that soak in the coffee for a few hours and then spray. I would also use the full strenth coffee and place it under places that are hving a problem.

andy lopez

Invisible Gardener

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