I have had long english cucumbers, peppers & tomatoes in the GH all summer. I have them in big pots since the GH has a gravel base. The cucumber did get powdery mildew. I didn't have a problem with any bugs or spider mites. The door is really easy to remove so it was off except for chilly nights.
We had a speaker the other night at the garden club meeting re: GH & cold frames and he had said that running a small fan in the GH is enough air movement to prevent the mildew and also spider mites. fan means having power to the gh tho
