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.
Plus, youâll have at least one sturdy, weight-bearing wall in place (usually your house or garage), so the three greenhouse sides can be built lighter. These structures are often less expensive than other greenhouse models and are good for growing herbs, seedlings, and some vegetables in places where space is at a premium. The disadvantage is, of course, that sunlight will be limited to only three sides.