Plastic mulch is extruded from clear polyethylene resin into sheets of film of varying widths and lengths. In its natural state, plastic is clear, so carbon black is added to make it black. Generally, the thickness is 1.0 to 1.1 mil (1 mil = 1/1000 inch) although thinner materials are available in high density
polyethylene. Because of the inherent physical properties of black plastic mulch, it modifies the micro-climate around plants, enhancing growth, yield, and quality of horticultural crops.
Over many years of experimentation and use since the late 1950's black plastic has proved to be a boost to agricultural productivity.