Soil Health indicators are measurable properties of soil or plants that provide clues about how well the soil can function. Indicators can be physical, chemical, and biological properties, processes, or characteristics of soils. They can also be morphological or visual features of plants. This device can work as a soil moisture indicator. The LED connected to the device will start glowing as the moisture level goes very low.

The basic idea of the working of the Soil Health Indicator Circuit is that the water can conduct electricity. Two probes connected at two points Probe1 and Probe 2 are dipped inside the soil. As long as the moisture level remains there, the bases of Q1 will remain at low voltage. We can assume that Probe 1 and Probe 2 are connected with each other. As soon as the soil becomes dry, the continuity of probe 1 and probe 2 gets disconnected and Q1 gets turned on hence Q2 gets turned on and overall the LED D1 starts glowing.