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.
Measure your location. Whether you build the greenhouse from scratch or build it with a kit, you should choose the size carefully. The larger the greenhouse, the more money it will cost to build and heat. The most popular greenhouse size is 8 by 6 feet (2.4 by 1.8 m).