In the past, research into greenhouse climate control was characterized by its strongly experimental approach to the practical problems associated with the industrially available analogue control equipment.
The experiments were conducted in production conditions at horticultural enterprises.
The need to avoid putting the crops at risk entailed a degree of experimental caution which imposed considerable limitations on research into control theory.
Accordingly, the experiments were mainly designed to determine empirically the optimum settings for the controllers installed at an enterprise and to try to improve their control capabilities by modifications and additions to their electronics.
Local conditions such as the area of the greenhouse, its structural state, the configuration and technical condition of its climate-control plant, and the climatic conditions obtaining externally made each experiment unique, so that the settings found could hardly be credited with any general validity.
The contribution of the research to increased insight into the fundamental control characteristics of the climate-determining process was very limited and threatened to be lost sight of in the shifting of control problems onto electronic extensions and additions to the control equipment.
The slightness of the fundamental insight into the control characteristics of the climate-determining process in a greenhouse must accordingly be regarded as the major reason that the high hopes for wider technical applications which accompanied the introduction of the computer into horticulture in 1975 were hardly capable of realization in practice.
The results obtained were less than spectacular, but did constitute an important step in breaking through entrenched views to reestablish research emphasis on scientific aspects of control theory.