If my greenhouse had openings to let in mice or rats, I would not be able to use it as a greenhouse. Are you unable to close yours? Al

Where there's one mouse there's more...and more...so if you wait to see what it is, you'll never get anything planted. A really good trap is the Tin Cat. You put the bait inside and the mice go in, but they can't get out and it holds quite a few. Then you take the trap somewhere to the woods or away from your house and pop the top open...and repeat as necessary, which you would still have to do with a trap that kills, but this is less messy(I just personally have a problem killing the little devils). You can also try covering your flats temporarily with plastic(poke holes on top for venting)or tulle netting. Mice can chew through either of these, but it might buy you some time while the plants germinate(and maybe place some birdseed somewhere to divert their attention). Another option is to start your peppers inside, then put the seedlings in the GH, since peppers need warmth to germinate well(75-85 degrees). HTH