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.
Greenhouse Covering. Whether you're replacing existing greenhouse coverings or building a greenhouse you're sure to find the best greenhouse covering at FarmTek. Greenhouse glazing is the material that covers the greenhouse frame and the most widely used materials are polycarbonate and poly film.
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.