Tagetes overwintering

Looks like at least three of us are going to try to keep some tagetes going through the winter. Mine will be in a cold unheated greenhouse. (Husband says “if we’re limiting the heating for us, I’m buggered if we’re heating a greenhouse!).
I’d really like to keep a few going - they’re “Cinnabar”. A tall single red strain that came from a friend who got the seed from Great Dixter. Apparently (she says) they’re “special”.
I just think they’re pretty.

I can see your OH point of view   mine will be in a cold gh too, I only heat in early spring. TBH with our frost record, I don't hold out much hope.  Although I do overwinter begonia semperflorens in the border soil. I lose some but many survive, usually the red ones.