Outside. I tried inside first. Because of the winds in my area, I thought the shadecloth would be safer. But it trapped heat and my greenhouse became an oven, even with the doors and vents open. My new cloth is outside. Hubby and daughter worked hard to come up with a plan to keep the shadecloth on the greenhouse while still allowing the vents to open, even in 70 - 80 mph winds. It dropped the inside temperatures by at least 10*.
Also, look into colors, materials and % coverage. My shadecloth is 50% white - its still very bright but cooler than black or green. Aluminet has a metallic outside - it looks like space blanket.
https://www.greenhousemegastor...
