There are now fully organic slug pellets available which contain ferric phosphate instead of metaldehyde.
Does 'Organic' have any meaning anymore? It used to mean either derived from an organism, a living thing, or in chemistry a substance containing carbon, I can't see an iron phosphate fits either of these descriptions. Although there is some dispute about exactly how safe they are they appear to be safer than the old metaldehyde ones, that is really nasty stuff that causes brain damage in mammals.
The makers claim it is 'Safe for wildlife', so does it only kill domesticated slugs? It does seem to be effective in very small quantities, no need to cover the ground in blue spots, three or four pellets in the vicinity of the affected plant seem to do the trick.
Remember it is a bait, it will attract slugs, so try to position it so it will attract them away from your plants rather than towards them. A thin line in a lawn where it meets a bed for example. Slugs and snails love lawns so try to attract them to it and stop them leaving.
I am told it also contains an unlisted agent to make it more effective that may be harmful (EDTA) and does not contain the bitter substance that made metaldehyde pellets unpalatable to other animals. Large amounts of iron is poisonous to other animals from humans to earthworms.
