Modelling of heating and evapo-transpiration processes in the plant canopy requires knowledge about plant physiology, which includes water uptake by the root, water transport in the stem to the leaf, and transpiration at the leaf; and also the knowledge of radiation and heat transfer processes in the plant canopy. The temperature and water content of the soil are also important for the root water uptake. Thus, the model for heating and vapor transfer in the plant canopy in this paper consists of a submodel for radiation transfer in the plant canopy, a submodel for the heating of the canopy, a submodel for the transport of water in the root-stem- leaf system, and a submodel for the evapo-transpiration in the plant.