Seven Notes on Organic Slug Control
And yes, I do know about those huge banana slugs on the rainy west coast that eat everything down to nubbins overnight. ;-) You simply have to be a LOT more vigilant than I do but these products work the same way for you (although you'll go through a lot more of them.)
And that's really the first lesson. There is no letup in slug control. Just when you think you've got them beat, a new crop comes along to eat holes in the tomatoes, level the lettuce and decimate the flowers. Ah well.
Try these tricks for effective organic slug control.
Organic Slug Control
There are products on the market containing different forms of iron (ferrous sulphate, iron sulphate etc) that are like ambrosia to slugs. They love the stuff but too much iron kills them. So you scatter this around and you're in charge.
Other Control Products
All other slug baits contain toxic poisons that pose a danger to pets and the environment (not to mention our kids if they mess about with it).
You can physically destroy slugs. If you put a board down on the garden soil, and turn it over in the morning, you'll find slugs aplenty under there. Stomp them.
Nightly Slug Patrol
You can go on slug patrol at night. A flashlight will show the slime trails on your plants and you can follow these to the culprit - stomping him/her. You have to do this regularly as slugs are hermaphroditic and will breed all by themselves - and regularly to give multiple generations.
You can put a copper barrier (sold for this purpose) around your flower beds. The interaction between the slug's natural moisture, the ground and the copper forms a small electric charge and the slugs won't cross it. Mind you, it is important to make sure there are no slugs "inside" the barrier when you set it up. And any bridge across it - leaves, stems, etc - will be exploited by slugs as they move about the garden at night.
There is the saucer full of beer trick to let the slugs drown. Put the saucer at ground level and fill it with beer. Do not have a dog or cat or you'll have a drunk dog or cat.
Any product containing yeast will do the same thing
Seems like a waste of good beer to me.
I do know folks who put their empty beer bottles on the ground in the garden with the neck opening tilted to ground level and they capture more than their share of slugs. Mind you, it's a heck of a wakeup call for the recycling folks.
For my money, I let the slugs eat a bit here and there without going nuts about it but I don't live in an area where they turn into banana sized critters either.
Control them with the iron phosphate for best and most environmentally sound results.