At this time the land for farming in Indonesia is decreasing while the need for vegetable food is increasing, the agricultural sector has an important role in building the long-term economy. In a hydroponic plant cultivation system there are aspects that need to be considered, such as water pH, water temperature, and dissolved nutrients in the water. The aim of this final project is to develop a hydroponic monitoring system using an IOT-based Firebase model whose results are displayed and monitored through an android application. This tool uses three sensors, namely the DS18B20 sensor, the PH-4502C sensor, and the DFRobot GravityTDS sensor. This system uses the waterfall method which includes Requirements, Design, Implementation, Testing, and Maintenance. System testing is carried out after going through the comparison process of temperature sensors, pH sensors, and TDS sensors. The retrieved data will reside in esp32 before being sent to Firebase and can then be monitored via the Android app. The system can also provide control if the plant lacks nutrient levels, after testing the entire monitoring system it was found that all sensors were able to read data with differences that did not exceed the maximum average difference limit and the Android application as a monitoring system was able to display sensor measurement data, and was able to control the nutritional content of water according to a predetermined value.