I still find the best method of controlling slugs is to attract predators into the garden, i have a small water feature with frogs in it, some logs and leaves at bottom of garden to attract hedgehogs and I don't put bird feeders out so they eat the slugs instead, i do have a bird bath to attract the birds, i will put feed out for the birds when the growing season is over.

Before I did the above none of the methods I found anywhere was effective and they only way was to go out 1.00am at night and pick them of my veg and flowers put them in a plastic sealed bag and then in the bin, as if you just chuck them over the fence they find their way back.

Now I hardly get any slug damage at all, and I have loads of plants slugs love like Hosta's. lettuce etc.