Design of a Microcontroller-Based Automatic Irrigation System for Greenhouse Farming in Jos, Plateau State

This project designs a microcontroller-based automatic irrigation system for greenhouse vegetable farming in Jos, Plateau State, North Central Nigeria. Jos has a temperate highland climate that is increasingly being exploited for off-season vegetable production in greenhouse structures, yet the limited availability of irrigation labour and the variable water requirements of greenhouse crops create demand for automated water delivery systems that improve productivity and reduce crop stress. The system integrates three soil moisture sensors placed at representative positions within the greenhouse growing area, a DHT22 temperature and humidity sensor to monitor the internal microclimate, and an Arduino Mega microcontroller that processes all sensor inputs and activates drip irrigation solenoid valves per planting zone. The control algorithm accounts for both soil moisture deficit and high ambient temperature readings to adjust irrigation frequency, providing more frequent short irrigation pulses during hot dry periods. A 16x2 LCD displays current sensor readings, valve states, and daily water volumes delivered. An SD card logger records all irrigation events for agronomic analysis. The system is powered from mains supply with a battery-backed UPS to prevent loss of irrigation during outages, which are common in Jos. Field testing over eight weeks on a tomato greenhouse crop demonstrated a 35 percent water saving compared to manual drip irrigation while maintaining comparable crop yield and fruit quality. Farmer feedback confirmed ease of use and low maintenance requirements of the implemented system. Keywords: automatic irrigation, greenhouse, soil moisture, microcontroller, Plateau State.