Baking soda is salt and limestone so I assume if you don't dilute it well enough, it would burn. I mix it up in gallons and use my sprayer to pretty much coat everything, in, around and under. I've never seen it burn when used in this mix but of course, test it out on your plants. I do reapply but not sure I am diligent enough to do it after every rain. I do it when I see those critters and think - ha, let's get a bit of fire on your tongue you nasty critters. It's the ultimate clinical way of handling pest management :). I think of it as giving them an alka seltzer gargle - blah!
I use this recipe for pretty much everything including aphids, Japanese beetles and slugs. I have tons of butterflies and honey bees so I assume it does nothing to the taste of the nectar.
It's been pointed out to me that you Hosta growers have areas that never dry up. It's just an old practice of mine not to let plants be wet overnight but can see the problem of drying leaves in shade :). Try it on a leaf and see if the slugs go to the unsprayed leaves. then check to make sure my remedy doesn't hurt your plants.
I did google baking soda + hosta and phytotech seems to use it quite a bit in starting new plants:
http://www.phytotechlab.com/pd...
HTH
Mindy
