I'm on day 5 of a hardening process for my seedlings. It's been mild (60s-70s during the day) here. I'm going out of town for a few days, during which the temp is supposed to be 50-60 night-day. Should I leave the seedlings outside for those few days (under an overhang, no direct sun or rain), or will 50F be too cold? This would be day 7 of the process.