Monitoring of temperature and humidity in a greenhouse with different growing media using ESP32 for spinach (Amaranthus sp.) cultivation

Abstract

Spinach (Amaranthus sp.) is a nutritious leafy vegetable whose growth is strongly influenced by environmental temperature and humidity. The instability of these factors due to climate change requires accurate monitoring to support successful greenhouse cultivation. This study aimed to monitor air temperature, air humidity, and planting media conditions in a greenhouse using an ESP32-based microcontroller system. Three planting media were tested: garden soil, organic compost, and cocopeat, with spinach (Amaranthus sp.) as the research subject. The system used an SHT31 sensor for air temperature and humidity, a DS18b20 sensor for media temperature, and a SEN0308 sensor for media moisture. Data were displayed on a 20 4 LCD and automatically saved to an SD card every hour for 30 days. Results showed that air temperature ranged from 24  to 35 , peaking at midday. The highest media temperature, both maximum and average, occurred in organic compost (31.49 ), followed by garden soil and cocopeat. Air humidity ranged from 54% to 91%. Media moisture content was highest in cocopeat (364%), followed by organic compost (38%) and garden soil (28%). Garden soil produced the most optimal growth, with an average height of 31.35 cm and 62 leaves on day 29. Organic compost yielded similar growth (30.32 cm and 58 leaves), while cocopeat showed the lowest growth (11.7 cm and 9 leaves). These results indicate that garden soil and organic compost is more suitable for spinach cultivation in greenhouse systems compared to cocopeat.