In DSM, nicotine dependence is included under the general definition of substance dependence.  The essential feature of Substance Dependence is a cluster of cognitive, behavioral, and physiologic symptoms indicating that the individual continues use of the substance despite significant substance-related problems.
The Best Materials to Cover your Greenhouse. 1  Glass: The traditional greenhouse covering, glass is the preferred material for permanence. 2  Film Plastic: Film plastic is one sixth to one tenth of the cost per square foot of a glass covered structure.
Typical costs: A small (6'x8' to 10'x10') prefabricated greenhouse kit can cost $500-$2,500 for a simple metal structure with plastic panels, a roof window to allow moisture and heat to escape, and a door.