Interest is increasing in the development of methods to automatically and continuously detect crop stress, water use, growth and nutrition in greenhouse crops. Some of these techniques are now being tried in commercial greenhouses and hold the promise of improved climate management for better yield and quality, and reductions in environmental impact. However, integration of automated crop monitoring with computer environmental control systems is not yet commonplace, and will depend on the development of computer programs which incorporate the most appropriate real-time crop data into dynamic models.