Wireless sensor networks for greenhouse climate and plant condition assessment

Spatially distributed environmental measurements at plant level can be used to create a precise and detailed representation of the climate at various regions inside a greenhouse. Climatic heterogeneity can cause significant differences in terms of yield, productivity, quantitative and qualitative characteristics of the plants, as well as the development of various diseases. This work presents: i) the assessment of wireless sensor networks (WSNs) operation reliability and accuracy in actual greenhouse conditions, ii) the development of a distributed monitoring system using a WSN in a commercial greenhouse, and iii) the analysis of the collected spatially distributed data for the investigation of possible problematic situations for the growing plants caused by climatic heterogeneity inside the greenhouse. A prototype WSN was initially developed in order to investigate the effects of the environmental conditions to the operation reliability of the network and assess its performance and the feasibility of its operation in a commercial greenhouse. The enhanced WSN was then installed in a commercial greenhouse to investigate the spatial variation of the existing environmental conditions. Analysis based on WSN measurements showed significant spatial variability in temperature and humidity with average differences up to 3.3 °C and 9% relative humidity and transpiration, with the greatest variability occurring during daytime in the summer period. There were conditions that favoured condensation on leaf surfaces and other problematic situations.