A green roof module for covering a portionof a roofing surface with vegetation, includes a tray forcontaining a growing medium and vegetation, a permeablemembrane, and a drainage board The tray has a biodegrad-ablebottom and a plurality of upwardly extendingbiodegradable walls about the perimeter of the biodegrad-ablebottom The biodegradable bottom is configured sothat water received within the tray can pass therethroughThe permeable membrane is provided below the biodegrad-ablebottom, and is sized and shaped so as to span thebiodegradable bottom and configured to allow water topass therethrough while inhibiting the growing mediumfrom passing therethrough The drainage board is providedbelow the permeable membrane opposite the biodegradablebottom, and has an upper surface for supporting thebiodegradable bottom and being surrounded by a pluralityof edges The drainage board is configured so that at leastsome of the water passing through the permeable mem-braneand received on the drainage board will be drainedaway from the tray.
