There are usually three methods of controlling slugs naturally that you’ll read about in gardening articles.
Handpicking or You Gotta Be Kidding Me
The first is hand-picking. Really! Some intrepid gardener wander their gardens at night, armed with a flashlight, a pail of soapy water and (hopefully) plastic gloves to handpick these creeping destroyers of all things leafy and fruity or flowery.
Pick ‘em up, drop ‘em in the soapy water and they’re gone.
Some of these folks even lay traps such as boards down on the garden, giving the snails a sense of a hiding-spot, then “Gotcha!”. This is way more work and dedication than I’ve ever recommended. (I did it once or twice though just to say I did it)
Beer or You Gotta Be Kidding Me
If you take some beer, put it in a saucer so the saucer is level with the soil slugs will be attracted to the yeast fragrance, crawl in to get a taste and drown. This is supposed to work but it never worked for me.
But there are several problems. First, dogs and cats drink the beer. Nothing wrong with that – it’s not enough to hurt them or make them drunk but it defeats the purpose of attracting slugs.
Rain and heavy dews dilute the beer.
It’s messy and drunk snails are no more fun that drunk people.
It’s a waste of good beer.
Iron Phosphate and I’m Not Kidding You
Slugs are poisoned by iron phosphate (iron filings) It’s in the soil everywhere but slugs don’t eat soil. So we put a bit of “food” around the iron, give it to the slugs and they die.
Organic, recycling the iron back to the soil, effective, easy, no clean-up, and it doesn’t waste good beer.
Shopping Resource for Controlling Slugs Naturally