Smart microcontroller-based automation system for garden maintenance is specially designed to improve the conditions of public garden by controlling plant watering, lighting and gate opening and closing without any human interference. The garden is taking care of itself through automated electronics devices, hence it is called smart automated garden. This system avoids the wastage of electricity and water in public gardens. Arduino is used to control entire functionality of system. Real Time Clock (RTC), soil moisture sensor, buzzer, motor required for water supply and motor required for gate control interfaced to ATMEGA328 microcontroller. Lamps in the garden are switched ON/OFF depending upon time set in RTC device and the lamps remain functional till the garden remains open. Soil moisture sensor is used to analyze moisture contents in the soil. Depending on moisture contents of the soil, water pump will turn ON and OFF. The gate is opened and closed by motor with closing indication controlled through ATMEGA328 microcontroller. The designed system is deployed and tested which has performed well and satisfactory with 88% and above accuracy and reduced the efforts of human in public gardens.