This Moisture Sensor can be used to detect the moisture of soil and thus to monitor if the plants in your garden need some water.

This sensor uses the two probes to pass current through the soil, and then it reads then resistance to get the moisture level. More water makes the soil conduct electricity more easily (less resistance), while dry soil conducts electricity poorly (more resistance). Compares to the other moistures sensor using the same moisture test method, this module has super long legs, making it suitable for actual applications.