Greenhouses are complex and nonlinear systems in which the inside temperature and humidity are deterministic parameters for the optimal growth of the plants. Several control methods have been developed to get an optimized microclimate. Physically both parameters are strongly coupled; hence, this paper proposes a novel fuzzy controlling method considering the temperature and humidity’s coupling effects; the controller is based on a validated greenhouse physical model and an evaluation of the correlation of both parameters. The results show the high performance of the decoupling method and the effectiveness of the fuzzy controller to manage the inside climate while saving energy. © 2015, King Fahd University of Petroleum & Minerals.