An innovative precision agriculture technological platform specifically conceived for improving water management and crop production in a key Mediterranean agro-economic fields such as viticulture is presented. The platform is based on a novel set of biosensors able to directly measure critical parameters of the plant water stress condition rather than acquiring indirect measures from the environment as currently done. These sensing nodes are organized in a wireless sensor network deployed on field and capable of acquiring, continuously, a large amount of data. Information is collected in a central hub and made available to a decision system and trained operators for optimization of the use of the water resource. Deficit irrigation practices are exploited to maximize crop water productivity and/or orientate the characteristics of the final product. Key features of the platform are low-power operation, wireless connectivity, ease of use, minimal maintenance requirement, minimum invasiveness or interaction with farming activities.