NwMtGardener said:
. . . When do you usually disassemble them?
. . . I was thinking I would roll up the sides maybe, halfway - so there was enough airflow for the plants in the ground, but a warmer microclimate above? We also have trouble with a long enough growing season to get RED tomatoes here in Montana! Has anyone tried anything like this? Do you think I need to be worried about pollination?
First I was thinking that you might be another person from the NorthWest
coast trying to eke out a little more warmth to your summer months but, you are almost in my neck of the woods MwMtGardener!
Welcome to TEG

!
Okay, I know what you mean by trying hard to have a RED tomato! I used to grow only SubArctic tomatoes when I lived at a higher elevation not too far from Lake Pend Oreille. We've got lots more short-season tomato varieties than I knew about back then, however.
Not too many big slicers, tho' . . . I think that any kind of protection for the plants should be helpful to you. And yes, rolling up the sides of your greenhouse should benefit the tomato plants. I had several tomato plants in the greenhouse thru last summer. They produced beautiful fruit!
The greenhouse is permanent but those "hoopies" are already out of the yard. That leaves the bigger hoop house/tunnel. It will come down in just a few days.
The tunnel is over 2 beds and all of the bok choy has been harvested from one and more bok choy seed planted. There's no reason to maintain much heat in there with that crop. I have left it up until about the 1st of July, one year. There were things like Malabar spinach growing in there.
The greenhouse has lots of basil right now. Soon, I'll just leave it open day and night. The exhaust fan can stay off. No plants can be left on the top shelf because of the heat but it won't be too bad elsewhere for something like basil. It could be that those plants will all end up sitting real close to the open door along about August. The basil will also be in the garden but it often looks to be in better health growing in containers in the greenhouse.
Best of Luck with Your Growing!
Steve