Where I live, slugs seem to made of anti-delphinium. Forget starting them in the ground, or even hardening them off on a table on the porch. As soon as i put a seedling outside and turned my back, they disappeared to the soil line.
I had to put them out much bigger and surrounded by slug bait. Once the plants got big enough (?? 1-2 feet??) they became safe and didn't even collect "slug bullet-holes".