Beer will work for the slugs, so long as they can fall in and not get out. Mine got smart and just learned how to drink the beer and make a clean get away. They are attracted to the yeast in the beer and they are supposed to drowned while trying to get it.
Salt also works well, but it can damage concrete, blacktop, and other materials.
I know you want organic, but there is a good snail and slug bait out there that is safe for animals, pets and the environment (it is in blue container I can’t think of the name).
Learn the correct way to grow a great garden. You do not just throw some seeds around and add water. There is alot more to gardening than you might think. http://www.backyardgardening.info
http://www.survivalistboards.com/