A Minimalist Automated Plant Growth Chamber System: Design, Implementation, and Experimental Use on Chili

Highlights An automated plant growth chamber was developed. The system is designed to maintain temperature, relative humidity, and light intensity and is supported by an intuitive UI with a maximum of five operational steps. The functional test result shows that the system is able to reach maximum and minimum temperature (5°C-50°C lights off and 10°C-50°C lights on), humidity (30%-99% RH), and light intensity (0-15,000 lx) as designed. The test also revealed that our system is able to maintain a horizontal temperature uniformity of 0.52°C. The uniformity is proved to be comparable to the commercial chamber datasheet available. Performance test shows that the system is able to maintain temperature and light intensity over the designed range. However, it failed to maintain relative humidity as designed. It is presumed that this failure is due to the use of a fixed-speed compressor-based refrigeration system. The system has been used to grow chili peppers (Biocarpa and Lingga). It is shown from analysis of variance (ANOVA) that specimens grown inside the Plant Growth Chamber System show a significant difference from the other specimens grown in the screen house or open field, especially in the vegetative phase. Abstract. Experiments concerning plants, such as breeding, cultivation, and germination, are significantly influenced by the surrounding environment, highlighting the importance of accurate climatic control. A plant growth chamber is a physical system designed to maintain climatic conditions inside the chamber. In this study, we present the design, development, and experimental use of an automated plant growth chamber system. The system can control three major climatic parameters—temperature, relative humidity, and light intensity—and is equipped with an intuitive user interface with a maximum of five operational steps. The chamber’s performance was evaluated in a continuous 10-h test. Results showed that the system can maintain temperature with an accuracy of 0.7°C relative to the setpoint and a horizontal spatial uniformity of 0.52°C. These results are comparable to those of several commercially available systems, demonstrating the system's reliability. The chamber was further used in a plant growth trial involving chili. ANOVA results indicated that specimens grown in our chamber significantly outperformed specimens grown in a screen house during the vegetative phase. Future improvements will focus on implementing a variable-speed compressor-based refrigeration system and a lighting system with an adjustable spectral profile. Keywords: Automation, Control, Growth chamber.