Dave, I have two greenhouses. One is dedicated to orchids and seedlings and the other "everything else tropicals". Because I wanted high humidity in both GH's, I decided to put a 4" layer of cypress mulch as the base (over clay soil) and then covered this with black floor fabric. I not only got my high humidity (just spray the fabric with water) but as a bonus I got great drainage and an easy-on-the-feet-and-legs surface. This is an inexpensive alternative and is easy to put down. Ken in Mississippi
