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.
1 Kits to build a permanent outdoor greenhouse start between $500 and $2,500 for a basic metal and plastic structure (typically 6'x6' to 10'x10'), but can cost $3,000-$15,000 for larger (12'x12' to 18'x20' and up), more elaborate and/or more durable models. A basic cold frame starts at $30-$100, but larger and more durable models can cost $100-$600. 2  Cold frames can also be constructed for free using recycled materials. 3  For more details, see How Much Does a Portable Greenhouse Cost.