Highly stretchable, robust, and resilient wearable electronics for remote, autonomous plant growth monitoring

Previously reported wearable strain sensors for monitoring plant growth have limited operating strain (<200%) on plants, intransparency, and uncertain stability and reproducibility, hindering their application in tracking plant growth. We report a transparent, conjugated polymer-based strain sensor that achieves robust and precise plant growth monitoring with an operating strain of over 400%. Through device engineering, the strain sensor is ultra-lightweight (∼45 mg), highly transparent (transmittance = 98.7%), environmentally stable (degradation rate = 0.0008 h −1 ), linear (R 2 = 0.996), reproducible (coefficient of variation = 14.4%), and resilient to humidity. The strain sensor also features a low Young's modulus (3.4 MPa) one order of magnitude lower than that of the tested leaf, thereby exerting negligible mechanical load and no observable impact on plant growth. Combining with wireless technology, we achieve remote, autonomous tracking of plant growth that unveils the sensitivity of leaf elongation to light/dark cycles challenging to obtain using other methods.