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Abstract Stem water potential (Ψ_stem) is a key indicator for assessing plant water status, which is crucial in understanding plant health and productivity. However, existing measurement methods for Ψ_stem, characterized by destructiveness and intermittency, limit its applicability. Microtensiometers, an emerging plant-based sensor, offer continuous monitoring capabilities and have shown success in certain vine and tree species. In this study, we investigate the efficacy of microtensiometers ability to monitor the Ψ_stemof cotton (Gossypium hirsutumL.) under three distinct irrigation treatments in Maricopa, Arizona, an extremely hot, arid environment. We analyze the diurnal dynamics of Ψ_stemacross the irrigation regimes and compare these measurements with midday leaf water potentials (Ψ_leaf) obtained using a dewpoint potentiometer. Our results demonstrate that the microtensiometer-derived Ψ_stemclosely follows known diurnal patterns of Ψ_leaf, tracking with vapor pressure deficit (VPD) and responding to variations in irrigation levels and soil moisture content. Time cross-correlation analysis reveals an 80-minute lag in Ψ_stemresponse to changing VPD under non-water limiting conditions, which shortens under water-limiting conditions. Additionally, we establish a robust linear relationship (R²_adj = 0.82) between Ψ_stemand Ψ_leaf, with this relationship strengthening as water availability decreases. Notably, we observe mean gradients of 1.2 and 0.06 MPa between soil vs. stem and stem vs. leaf water potentials, respectively. Moreover, Ψ_stemdata proves to be more sensitive in distinguishing between irrigation treatments earlier in the growing season compared to Ψ_leaf, leaf temperature and leaf gas exchange parameters. These findings highlight the utility of microtensiometers as valuable tools for monitoring water status in smaller-stemmed row crops such as cotton.