As a result of inadequate advanced controller system for post-harvest storage facilities there is high post-harvest wastages of agricultural produce in Ethiopia that adversely affect security of food and economic growth. Therefore, the research aims to develop a fuzzy PID self-tuning control system by considering the needs of smallholder farmers in Ethiopia who produce perishable goods. The research utilizes a self-tuning fuzzy logic controller to adaptively adjust PID parameters according to varying storage conditions to addresses a notable gap in existing literature, which often relies on simulations without sufficient real-world validation of evaporative cooling storage systems. The obtained result from MATLAB Simulink step response for transient and steady state performance parameter of both PID and fuzzy PID controllers showed that the temperature rise times were 0.4428 and 0.1495, settling times were 0.8029 and 0.8003, settling max were 22.0030 and 22.0, and for humidity the rise times were 4.7231 and 4.7316, settling times were 8.4860 and 8.4821, seconds respectively, and both controllers had 0% overshoot for two input conditions. Under ±50% gain variation, the PID exhibited more divergence than the fuzzy PID. Thus, simulation results indicates that in more dynamic and complicated settings the fuzzy PID self-tuning controller has superior stability and flexibility. The Proteus simulation validated the reliability, robustness, and consistency of the developed fuzzy PID self-tuning controller with the Simulink model. The desired setpoints of 22°C and 93% humidity successfully achieved in closed-loop experimental tests on developed prototype by adjusting airflow and water flow rates based on the feedback from ambient conditions of 28°C and 52% humidity. This research offers a robust solution for preservation, contributing to agricultural engineering with potential applications in various storage and transportation environments. Keywords: Agricultural Engineering, Experimental Validation, MATLAB Simulink, Post-harvest Preservation, Proteus Simulation.