Agriculture sector has been greatly influenced by the recent advances in electrical engineering. Nitrogen (N), from fertilizer, remains one of the largest input to surface and groundwater contamination, resulting in environmental and human health degradation. This paper explores the use of wireless potentiometry in field settings for in situ N monitoring. We report a disposable IoT gardening soil sheet, capable of analyzing real-time soil nitrate concentration during leaching and irrigation events. The nitrate doped polypyrrole ion selective electrode (N-doped PPy ISE) sensor array sheet features a fault tolerant circuit design multiplexed to an oxidation and reduction potentiometer that can rapidly detect nitrate levels in soil leachates. Measurement data are transmitted via Waspmote ZB Pro SMA 5dBi radio, 6600mAh rechargeable battery, 7.4-volt solar panel, and a Meshlium ZigBee PRO access point to cloud server and mobile device. This paper investigates the gardening IoT sheets as a viable tool for in situ nitrate mapping, and to potentially help everyday home and commercial gardeners reduce excessive fertilizer application. (C) The Author(s) 2018. Published by ECS.