An exemplary tray for a module of a green roof system includes a bottom surface and a sidewall extending upward from the perimeter of the bottom surface to a lip. The tray may be formed of thermoplastic fiber. The bottom surface has one or more raised portions that divide the bottom surface into a plurality of cells. The raised portions form water drainage channels. At least the bottom surface of the tray has a porosity of about 50 percent to about 80 percent.
