Climate change has intensified environmental variations like rising temperatures and irregular rainfall, stressing vegetable crops and reducing productivity, especially in family farming, which relies on natural conditions and lacks affordable monitoring technologies. In this context, this work proposes developing a low-cost intelligent system based on Internet of Things (IoT) technologies to identify climatic conditions that may cause plant stress. The system integrates temperature, air humidity, soil moisture, and luminosity sensors connected to an ESP32 microcontroller, which sends the data to an MQTT broker and subsequently to a Flutter-based mobile application that displays and stores the measurements in Firebase Firestore. The solution will be evaluated through a comparative experiment between two cultivation scenarios—one using the system and another conducted without technological support—in order to assess its effectiveness in reducing plant stress and improving the quality and productivity of the crop.