what is hydroton for?

[orchidrandall]

What is the layer of hydroton for in orchidariums? If its for drainage and keeping the plants out of water and humidity.. would gravel work as well?

[shakkai]

It is partly for keeping the plants out of water, and for that gravel would work just as well. When I had my orchids in a recycled aquarium, I simply used the same kind of gravel as I had had for the fish tank. The advantage I have found with Hydroton/LECA is that it is much more porous and actually does help in raising humidity. I have found that for me trays filled with gravel have little or no effect on surrounding humidity.

[Tindomul]

And it weighs ten times less than gravel does.