Abstract— Considering the prevalence of Ambient Intelligence, this work aims to enhance the interaction between farmers and Intelligent Environments, in order to support their various daily Agricultural activities, aspiring to improve the quality and quantity of cultivated species. Towards this direction, the Greta system was designed and developed, following a user-centered design process, permitting farmers/agronomists to easily monitor and control an Intelligent Greenhouse via a set of useful and usable applications. Greta offers a progressive web app (PWAs) targeting PCs, handheld devices, and technologically-enhanced artifacts of Smart Homes, while it also delivers an Augmented Reality application that visualizes the greenhouse’s interior conditions in a sophisticated manner, and provides context-sensitive assistance regarding cultivation activities. In more detail, the system interoperates with the ambient facilities of an Intelligent Greenhouse allowing end-users to: monitor the conditions inside the greenhouse, remotely control the state of various actuators, be notified regarding the available/active automations, be aware of the optimal conditions for their plants to grow and receive relevant guidelines, be informed regarding any diseases, and communicate with experts for receiving treatment advice. This work describes the design methodology and functionality of Greta, and documents the results of a series of expert-based evaluation experiments.