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.
Our Commercial Greenhouses are perfect for schools, agriculture programs, commercial and retail growing operations. Commercial Greenhouses are larger greenhouses often made with galvanized steel frames that can accommodate large growing operations or horticultural programs. Our commercial greenhouse kits are ready for your local contractor to build or, our greenhouse construction team can build your organization a turnkey greenhouse.