# Smart Hydroponic Cultivation System for Lettuce
## 2 Materials and Methods
### Monitoring and Control System
\begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline
**Features** & **Own** & [18] & [20] & [21] & [23] & [24] & [25] & [26] & [28] & [29] & [31] \\ \hline \hline \multirow{4}{*}{Monitoring} & A. Temperature & X & X & X & X & X & X & X & X & X & X \\ \cline{2-11}  & RH & X & X & X & X & & & & X & X & X \\ \cline{2-11}  & A. \(CO_{2}\) & X & & X & X & & & & & & \\ \cline{2-11}  & light level & X & X & X & & X & & X & & & & \\ \cline{2-11}  & NPK & & & & X & & & & & & \\ \cline{2-11}  & pH & X & & & X & X & & X & X & X & X \\ \cline{2-11}  & CE & X & X & & & X & X & X & X & X & \\ \cline{2-11}  & TDS & X & X & & & X & X & X & X & X & \\ \cline{2-11}  & DO & & & & & & & & & & \\ \cline{2-11}  & Energy & & & & & & & X & & & \\ \cline{2-11}  & W. Temperature & X & & & X & X & X & & X & & X \\ \cline{2-11}  & Water level & & & X & & X & X & & & & \\ \hline \hline \multirow{4}{*}{Automatic control} & A. Temperature & X & X & X & & & & & & & \\ \cline{2-11}  & RH & X & X & & & & & & & & \\ \cline{2-11}  & A. CO\({}_{2}\) & & & & & & & & & & \\ \cline{2-11}  & Photoperiod & X & & X & X & & X & & & & \\ \cline{2-11}  & pH & & & & & X & & & & & \\ \cline{2-11}  & CE & & & & & & X & & & & \\ \cline{2-11}  & TDS & & & & & & X & & & & X \\ \cline{2-11}  & DO & & & & & & & & & & X \\ \cline{2-11}  & W. Temperature & & & & & & & & & & \\ \cline{2-11}  & Water Flow & X & X & X & X & X & X & X & X & X & X & X & \\ \hline \hline \multirow{4}{*}{Friendly Interface} & Mobile app & X & & & & & X & & & & & & X \\ \cline{2-11}  & Web app & X & X & X & & & & & X & X & X & X & X \\ \cline{2-11}  & Local screen & & & & X & & & & & & & \\ \cline{2-11}  & Alert system & X & & & & & & & & & & X \\ \hline \hline \multirow{2}{*}{Adaptable to diverse crops} & X & X & X & X & X & X & X & X & X & X & X & X \\ \hline \hline \multicolumn{11}{c}{Assessed in crop trials} & X & X & X & & X & & & & X & & X \\ \hline \end{tabular}
\end{table} 
Table 6: Comparison with related studies. network. This feature greatly enhances the system's accessibility, enabling users to monitor and adjust crop parameters from any location with Internet access. An additional contribution is the automatic email alert system triggered by data transmission failures, which strengthens the system's operational reliability. This is only comparable to the WhatsApp alert system used in [31]. Regarding experimental validation, this study not only presents the behavior of environmental variables but also evaluates phenotypic and nutritional characteristics of the harvested crops like fresh and dry weight, number of leaves, plant height, root length and content of proteins, fiber and carbohydrates. This comprehensive approach sets it apart from studies such as [20; 23; 24; 25; 28; 31], which do not assess the direct impact of environmental conditions on final crop quality. Despite the proper performance of the proposed system, one of the main limitations identified compared to [24] is the absence of an automated control loop for adjusting nutrient solution variables such as pH, EC and TDS. In its current version, these adjustments must be made manually. It is anticipated that future implementations will incorporate control mechanisms and algorithms capable of regulating these variables in real time, thereby improving nutrient solution management. Additionally, although an IoT architecture based on five layers is proposed, the current implementation does not incorporate artificial intelligence for predictive analysis, as seen in the system developed by [23]. ## 5 Conclusions

This article presents the development of a smart agriculture system that monitors and controls various environmental variables, supported by a web application and a mobile app for data visualization. Additionally, this study analyzed the growth of lettuce (_Lactuca sativa_) in hydroponic systems, evaluating three treatments with different nutrient concentrations: 50%, 75% and 100% of the Steiner solution, respectively.