Simply change something enough to make the bad habit less convenient or satisfying, or offer a better option. If the cats start sleeping somewhere I don't want them to be, I put something in the spot for a few days that encourages them to find a new place. By the time the "something" is removed, they've found a new place. It's best not to give a DH example. (See, the training has worked on me too. And removing the cats or DH is not an option!) Ok, sometimes it works, at least.So what to do with slugs? I decided to try coffee. First, I used the coffee grounds from my french press. However, that didn't go too far. So, I coarsely ground up some old coffee beans I had. Now, I don't know that it is the coffee that has much effect on them, but I thought they might not like the texture. Again, the purpose is simply to make things different enough that they decide to go elsewhere. I once used some old sheep wool trimmings around broccoli seedlings with success too.
All but one of the seedlings have new growth now (photo above), even one of the stubs. The other stub might still pull through too. The new growth is not being eaten, either.
If nothing else, I'm hoping the training simply distracts them long enough for Petunia to show up and eat them.