If they only need BRIEF cold periods, at Zone lows like 15-20 F some nights, I'm thinking of a cold frame that would really be a COLD frame!
A shade cover, then insulation over the soil, then either ice blocks, dry ice, or an air conditioner with a long cord. Chill 'em for a few nights, and hope that's enough.
But I'm guessing form other posts that the short answer would have been "probably not". Sigh!
