Pot plant production in the green house is most of the time under high relative humidity and frequent irrigation. While, during shipping and retailing plants may be exposed to high temperature and infrequent irrigation. These unfavorable post production environments can cause rapid substrate drying, desiccation of plants and acceleration of senescence and short shelf life. To reduce water loss and its subsequent negative effect on the qualities of pot plants, it is important to develop techniques that can be engaged to reduce transpiration and preserve postharvest quality for extended time. Anti-transpirant agents are compounds or provisions capable of reducing water loss from leaves of plants. These agents can be grouped into three: film-forming types, reflecting materials and physiologically active stomatal closing compounds. The interest of this book is limited to physiologically active stomata closing type compounds. However, in latter sections, the possibility of getting a positive combined effect by blending physiologically active compounds (PAC’s) with a film forming anti-transpirant is also covered.