University of Maine Cooperative Extension begins collection of greenhouse plastic for recycling Sept. 25 with 16 drop-off sites across the state. Disposal is free of charge through Dec. 15 to all Maine growers who register.  The target material for recycling is clear, low-density, polyethylene (LDPE#4) plastic typically used to cover greenhouses, high tunnels, hoop houses read more UMaine Extension greenhouse plastic recycling collection starts Sept. 25