Developing a pragmatic pattern for timely learning crop growth information is significant in promoting high-quality agricultural production. Herein, an electrochemical sensing mode is designed for in-situ monitoring plant hormone (indole acetic acid as a typical example). To simplify the available electrochemical procedure with separate division of sensing interface decoration and liquid electrolyte addition, a bi-functional electrolyte, with superior quality of electron conduction and ion mass transfer, is built by exploiting the excellent conductivity of carbon-based nanostructures and the dynamic redox cycle between phenols and metal ions, endowed with the integration between conductive medium and semi-solid electrolyte. Since the one-step decoration of gel electrolyte, the sensing interface greatly simplifies the testing procedure without adding liquid electrolytes. With fascinating merits of integrative carbon-based gel electrolyte, electrochemical sensing toward in-situ tracing indole acetic acid with attractive simplicity and practicability, fulfilling the goal of acquiring information on plant growth status in timely manner.