Abstract
The increasing demand for sustainable agricultural production, coupled with climate variability, irregular rainfall, and water scarcity, has intensified the need for intelligent farming technologies capable of improving crop productivity and resource efficiency. This study presents the design and implementation of a low-cost IoT-based embedded system for automated greenhouse environmental control to support precision agriculture in Nigeria. The objectives of the study are to develop an ESP32-based smart greenhouse monitoring and control system, monitor key environmental parameters such as soil moisture, temperature, and humidity in real time, implement automated irrigation and climate control mechanisms, and provide a cost-effective solution suitable for resource-constrained farming environments. The proposed system integrates a capacitive soil moisture sensor, DHT11 temperature–humidity sensor, ESP32 microcontroller, relay modules, water pump, and ventilation fan for environmental regulation. Environmental data acquired from the sensors are processed by the ESP32, which automatically activates irrigation and ventilation systems whenever measured parameters exceed predefined threshold values. Experimental evaluation demonstrated reliable sensor performance, with soil moisture levels between 10% and 60% corresponding to sensor voltages ranging from 2.85 V to 1.35 V and ESP32 ADC values between 3530 and 1680. The irrigation system operated at a soil moisture threshold of 35%, activating the pump within 1.0–1.2 s, while the ventilation fan activated at 28°C to maintain thermal stability. System response time ranged from 330 to 600 ms. Crop growth experiments conducted over six weeks showed improved plant growth of 31.2 cm compared to 23.0 cm under manual irrigation, while water consumption decreased by 34%. The system demonstrated high operational reliability and effectiveness for sustainable smart agriculture applications

Key words: Automated Irrigation; Embedded System; ESP32; Greenhouse Control; Soil Moisture Sensor; Temperature Monitoring