At present, people who live in the countryside tend to move downtown in order to get jobs. As a consequence, only elders and children live in their hometowns with plenty of land left uncultivated. The aim of this research is to build cheap small gardening robots to help people grow plants in small yards as a hobby via a long-distance communication system. In this research, two robots composed of Raspberry Pi and ESP32 microcontrollers, which are low-price controller boards and convenient to buy within the country, were constructed. The robots can be controlled from long distances using Android smartphones. The capacities of the two robots with the two types of microcontroller are compared and discussed. To measure the soil moisture content, two types of moisture sensor, which are capacitive and resistive sensors, were implemented in this project. There are two main functions of the proposed model, which are weed cutting and watering plants. Moreover, a decision-making watering system was implemented and connected to moisture sensors and sprinkler controllers placed in the user’s garden. The robots were placed in the northern region of Thailand, while the user stayed in the central region and remotely controlled them with a smartphone for three months. The results show that the automatic watering system is better than a manual watering system since the plant growth rate for the automatic watering system was 20% higher than that for the manual watering system.