I wanted to place my heat and light loving orchids in the greenhouse along with the tomatoes and peppers for the summer, however, the light levels were too high for Cattleyas, even with the 45% poly shade cloth on the greenhouse.
After giving the problem some thought I came up with a workable solution: a temporary shade.
Using a folding frame that I had for camping I made a tent of shade material that came with a blow-away greenhouse some years ago.
Now, under the temporary cover, the light level during mid-day is about 3,000 foot-candles, which is ideal for Cattleyas. It is not pretty, but it works. It is a simple matter to add or remove the tent as needed.