This document describes a smart soil moisture control system for plant watering based on IoT using an Arduino Uno. The system uses an FC-28 soil hygrometer sensor connected to the Arduino to measure soil moisture levels and send signals to control irrigation pumps. The Arduino software allows the user to monitor soil conditions, select plant types from a library to determine watering needs, and control irrigation pumps accordingly. An experiment showed the system could efficiently water agricultural fields based on soil moisture levels and reduce water and labor costs while increasing crop yields.