The application of advanced agricultural technologies such as hydroponics and the Internet of Things (IoT) has the potential to improve cultivation system efficiency and sustainability. This study evaluated the effect of nutrient solution concentration on hydroponic lettuce cultivation (Lactuca sativa L. cv Rodhenas). Steiner nutrient solution was used at three concentrations (100, 75, and 50 %, corresponding to treatments T1, T2, and T3, respectively). The experiment was conducted using a completely randomized design, with three treatments and 14 repetitions per treatment, for a total of 42 experimental units. The goal was to reduce the amount of nutrients used while maintaining crop quality and minimizing environmental contamination associated with nutrient leaching. This study also demonstrates the design and implementation of a real-time visualization of variables using IoT technology. The monitoring system was based on a digital temperature and relative humidity sensor connected to a wireless module that transfers data to the cloud, allowing real-time visualization of variable behavior on mobile devices. Cultivation with nutrient solution at 100 % concentration resulted in superior lettuce growth and the highest chlorophyll concentration. This treatment also outperformed the others by nearly 100 g in biomass and showed a significant reduction in fiber content, decreasing to 0.38 % in T2 and 0.46 % in T3.
Moreno-Aguilera et al. (2025) studied this question.