No they are plastic. It is a very heavy plastic.

I'll keep trying with them. I'm going to pick up a few other plants from another location and give them a try in the same bed. I may have to place them in the same pots that I have the others in but my try to use a wicking cloth so I don't have as many tubes running in the area since I have extra water in the bottom of the bed. I did have a problem with water flow in this bed early on as I was trying to get the syphon working properly so I'm wondering if that may have stressed the plants some.