<![CDATA[Hydroponic cultivation in a greenhouse requires continuous monitoring of temperature and nutrient solution pH to maintain suitable growing conditions. However, manual monitoring makes it difficult to obtain environmental information in real time. This study aims to develop an Internet of Things (IoT)-based temperature and water quality monitoring system for a hydroponic greenhouse using an ESP32 microcontroller. The research employed the Research and Development (R&D) method, which includes needs analysis, system design, product development, implementation, and testing. A DHT11 sensor was used to measure air temperature, while a pH-4502C sensor was used to measure the acidity level of the hydroponic nutrient solution. Temperature readings were displayed on a 16×2 I2C LCD, while pH data were processed by the ESP32 and transmitted to the Blynk application via Wi-Fi. The test results showed that the developed system was able to measure temperature and pH values and display the measurement results in real time through the LCD and Blynk application. The system can therefore support remote monitoring of temperature and nutrient solution pH in a hydroponic greenhouse. Keywords: Hydroponic Greenhouse; Internet of Things; ESP32; DHT11; pH-4502C Sensor. Abstrak Budidaya tanaman hidroponik di dalam greenhouse memerlukan pemantauan suhu dan pH larutan nutrisi secara berkala untuk menjaga kondisi lingkungan budidaya. Namun, proses pemantauan secara manual menyebabkan informasi kondisi lingkungan sulit diperoleh secara real-time. Penelitian ini bertujuan mengembangkan Sistem Pemantauan Suhu dan Kualitas Air pada Greenhouse Hidroponik Berbasis Internet of Things (IoT) menggunakan mikrokontroler ESP32. Metode penelitian yang digunakan adalah Research and Development (R&D), yang meliputi analisis kebutuhan, perancangan sistem, pengembangan produk, implementasi, dan pengujian. Sensor DHT11 digunakan untuk mengukur suhu udara, sedangkan sensor pH-4502C digunakan untuk mengukur tingkat keasaman larutan nutrisi hidroponik. Hasil pengukuran suhu ditampilkan pada LCD I2C 16×2, sedangkan data pH diproses oleh ESP32 dan dikirimkan ke aplikasi Blynk melalui jaringan Wi-Fi. Hasil pengujian menunjukkan bahwa sistem yang dikembangkan mampu melakukan pengukuran suhu dan nilai pH serta menampilkan hasil pengukuran secara real-time melalui LCD dan aplikasi Blynk. Sistem ini dapat mendukung pemantauan suhu dan pH larutan nutrisi pada greenhouse hidroponik dari jarak jauh.]]>
