This paper introduces the photosynthesis-stomatal conductance coupled model, well known and frequently used in the studies of vegetation-atmosphere interaction, to be incorporated into the studies of modeling greenhouses’ microclimate. The use of this model, unlike many of other models
in the literature, allows accurate modeling of stomatal conductance for many plant types and under several environmental conditions. It also guarantees
the modeling of the photosynthesis process ,which is important for microclimate and CO2 enrichment purposes, due to the direct coupling between
photosynthesis and stomatal conductance in this model. Although the many advantages of this model, the many details associated with it may be the
reason behind not being used in greenhouse microclimate modeling studies. Thus, this paper comes with an aim of facilitating the use of this model and
encouraging modelers of greenhouses’ microclimate to use this powerful model by providing them the necessary background for the treatment of the
model in a well organized form that contains all the necessary and required information they may need in their use of the model. In this paper, the
photosynthesis-stomatal conductance coupled model is introduced by first illustrating briefly the biochemical background of the photosynthesis process
and then introducing the accurate biochemical model that represents it. Then the photosynthesis-stomatal conductance coupled model is presented with
its analytical solution methodology that gives accurate estimation of the photosynthesis rate and the stomatal conductance. Finally, validation of the
model results with available experimental data is performed for a representative crop type under different environmental conditions. This validation
proves the accuracy of the model in predicting the photosynthesis rate and in turn the stomatal conductance.