Do orchids need UV light?

[susiep]

I am building a new shade house for my 'chids. They have been grown outside under screen. Or in the shade of palm trees. I had to add a plastic sheet (3mil) over the top of the old shade house because the plants were getting too much water leading to fungal rot.

My question is: Will my plants miss the UV light they are getting now if I add a solid plastic top to the new shade house which blocks almost 100% of UV rays?

I was looking at this product at Home Depot.
http://www.palramamericas.com/docs/u...v_04-15-08.pdf