A monitoring system is presented for monitoring plants' conditions in one or more plant growing areas. The system comprises: a data collection system configured and operable to provide characterization data about plants in said one or more plant growing areas, the data collection system comprising data collection modules of at least first and second different types, the first type data collection module comprising a first imaging device of predetermined first optical properties and the second type data collection module comprising a second imaging device of predetermined second optical properties different from the first optical properties, the characterization data provided by at least one of the first and second imaging devices being indicative of various parameters of the plants being imaged; and a control system configured and operable to be in data communication with an analyzer to be responsive to operational data received from the analyzer and being based on analysis of the image data indicative of one or more plants being imaged by the first type imaging device, to selectively activate the second type imaging device to apply the second type imaging to at least a part of said one or more plants.