Abstract As global concern for food security continues to grow, modern monitoring technologies are playing a pyramidally crucial role in the agricultural sector. However, in the face of complex and fluctuating light requirements during crop growth, the further development of environmental monitoring technology is constrained by both the complexity and variability of environmental conditions and the limited accuracy and functionality of current light sensors. Herein, a self‐powered all‐inorganic tin‐lead (Sn‐Pb) perovskite photodetector (PD) is reported, and a novel all‐in‐one engineering approach utilizing benzenesulfonyl hydrazide (BSH) is incorporated to effectively enhance the photodetection performance of the PD. The BSH molecule plays a pivotal role in balancing and mitigating crystallization and grain growth processes of Sn‐Pb perovskite, while also inhibiting the oxidation of Sn 2+ and the formation of Sn vacancy defects in perovskite film. Consequently, the optimized champion PD reaches a responsivity of 0.36 A W −1 and a detectivity of 1.74 × 10 13 Jones at 650 nm. Benefitting from its excellent performance, the prototype of a light sensor employing PDs achieves specific detection of red and blue light in a simulated lighting environment required for plants development. This research not only presents a feasible strategy to improve photodetection performance of Sn‐Pb perovskite PDs but also provides novel insights for designing monitoring and feedback systems in intelligent agriculture applications.