Thanks for sharing. I understand that they need to be ground very fine. I hate slugs.

I have a trick in my anti-pest arsenal that seems to work fairly well for me. I place lava rocks around each of my bedded dahlia stems. They must be lodged down into the soil somewhat and touching each other so as to be inpenetrable by slugs. I assume the silica in the lava rocks would slice up any of the slugs attempting to "cross over".

Window screen; cut edge up. Slugs can't cross them without slicing and dicing themselves.
{{gwi:641401}}

I've tried the crushed eggshells; all it did was encourage the squirrels to dig around my tubers...

My Dad use to bury a bowl to ground level and fill it with beer and the next day it would be full of wasted slugs. Not a bad reason to have a beer party,LOL