Should I keep plants in unheated greenhouse with huge temperature swings?
I'm in zone 7B and the greenhouse is shaded until around 9, then still partially shaded until 10 or 11 and then it gets the full brunt of the afternoon sun. It's just starting to warm up here, with nights around 40 F and midday temps around 50 or 60 now. The greenhouse goes to the 40s or high 30's at night like outside, but is always at least a couple of degrees warmer than outside even on cloudy days, around 55 F. Sunny days, it's at least 10 degrees warmer than outside and if its sunny, and the outside temp is mid 60's , it can reach 87F inside, and remain at 80 F even with all doors and vents open. That's almost a 50F temperature gradient!
I'm on spring break, so I could check on them them on weekdays, but I only come back on weekends from college, so I may not be able to ventilate if it gets sunny. I have 2 potted blueberries, a couple of salad greens in a raised bed, some swisschard just seeded in pots, several pots with sown seeds, and two potted grapes in there right now. Should I move them out or is it okay to leave them inside? Will the high heat and cold nights damage plant growth? Blueberries seem to put on more leafs than blueberries outside and grapes inside the greenhouse have already had budbreak while grapes outside haven't even had bud swelling..