In a greenhouse, mold is your worst enemy. Even poking a few holes won't do a thing. You'd need a proper blower to keep a constant breeze through there.
If you have NO choice but to dry outdoors, a tarp tied between 4 trees over the lines your buds are hanging from would be less mold risk, but of course it looks kinda obvious.
Do you have a spare room or even a spare closet in a room that can be air conditioned or fit a dehumidifier in there?