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,
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,
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
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
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.
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.