Hydroponics is an agricultural method where plants grow with water and mineral nutrient solutions. For a good production of vegetables, it is essential to keep within an optimal range the values of the variables that influence growth: temperature, pH, electrical conductivity and frequency of irrigation. This article compares three cultivation sub-systems NFT-I, FR and Soil. Additionally, it describes the IoT computing for monitoring the principal variables: temperature, pH, electrical conductivity and frequency of irrigation. This prototype allows notifying the farmer about the current status of each variable through Telegram social network and a Web site. The methodology was as follows: start planting the same day in the three sub-systems, controlling the values of the variables obtained by the sensors, and notifying the farmer when the values exceed the established limits, then the weight, the number of leaves, length and width were measured. The results have shown that this system can reduce electricity consumption by 97.9%, furthermore, use green computing approach with solar panel energy supply. Finally, lettuce production was good, and in terms of weight, the number of leaves, length and width, followed the relationship FR > NFT-I > Soil.