This study proposes a homeostasis-based affective system with emotion and mood as a way to communicate a plant's health state and environmental needs to preschool and primary school children. A system is proposed that expresses mood and emotion to express the plant's health state and its affective reaction to user-induced environmental changes respectively. A long-term goal is to enhance empathic reasoning in children and respect for plants and life in general, using affect as a communicative interface (even though the underlying system is not emotive per se). A fundamental issue addressed in this work is to what extend it is useful to add affective communication to a system that is otherwise non-affective (plants in our case) in order to better understand that system's state. A computer simulation of the affective plant was tested (n=7). Our results suggest that children can identify the simulated plant's needs and state based on graphically expressed affect, and can act to enhance the homeostasis of the plant.@en