There are plenty of snail baits that work wonders. Remember the salt sprinkling your mother always told you would work will kill your plants in large enough amounts.
Also if you have pets or kids avoid products with metaldehyde at all costs.
There is a secret weapon out there though that you probably have in your pantry and enjoy every morning. Nature magazin suggests a nutty, bold double espresso. Researches have discovered that slugs and snails hate caffeine. Robert Hollingsworth of the United States Department of Agriculture'sAgricultural Research Service located in Hilo, Hawaii, and his colleagues were testing caffeine sprays and noticed that a 1 to 2 percent caffeine solution killed nearly all the slugs and snails within two days. Concentrations as low as 0.01 percent deterred the snails completely. For a little perspective, a cup of instant coffee contains about 0.05 percent caffeine, and brewed coffee has more.
A cup of drip brewed coffee has about 115 milligrams of caffeine.
An espresso (and percolated coffee) about 80mg,
Instant coffee has about 65mg of caffeine.
Drip brewed coffee is about twice as strong as that instant junk, which makes it a much more effective combatant. I wonder what my favorite bold and earthy Java roast brewed in my French press would do? Coffee grounds are already recommended as a home remedy for keeping slugs and snails at bay. Grounds repel slugs, but a caffeine solution is much more effective. I can attest, I've had good results.
How does caffeine repel slugs and snail? Caffeine is an alkaloid compound that acts as a stimulant in humans, which why I drink so darn much of it. Alkaloids are usually derivatives of amino acids and most alkaloids have a very bitter taste. Caffeine is found in the beans, leaves, and fruit of over 60 plants, where it acts as a natural pesticide that paralyzes and even kills certain insects feeding on the plants.
Bottom line: caffeine is effective. Keep in mind also that the United States bans metaldehyde residues in food, but classifies caffeine as safe. It may even qualify as organic (and hopefully also free trade).
Nursery addict, plant enthusiast, all around botany geek.
Gardening has always been a great passion of mine, one passed on to me by my mother, and her father before that. My goal is to parlay my passion to the following generations, to make the world a greener place, one yard at a time.
Gardens are a form of autobiography. --Sydney Eddison