Growth‐Compatible Low‐Interference Flexible Sensors for Long‐Term In Situ Monitoring of Plant Growth

Continuous in situ plant growth monitoring is essential for precision agriculture. Flexible electronics offer a non‐invasive solution, yet balancing measurement sensitivity with minimal biological interference remains a key design challenge. Here we report two growth‐compatible, low‐interference flexible sensors for fruit and stem monitoring, both based on the resistance strain effect. Each integrates a gold strain gauge with a geometrically engineered PDMS substrate tailored to the target organ. For fruit, an annular double‐wall multi‐chamber structure fits over the fruit, deforming with radial growth while reducing mechanical constraints and contact area. For stems, a cylindrical spiral structure wraps around the stem and gradually opens to accommodate increasing circumference. Device dimensions were determined via theoretical analysis and finite‐element simulations, and the sensors were fabricated using standard micro/nano‐techniques. Both designs exhibit linear and reversible resistance–diameter responses. In situ experiments confirm continuous monitoring capability, and a 10‐day attachment test shows no surface damage, validating growth compatibility and long‐term stability.