Jul 12, 2021 · This concept is easy to understand. It is the percentage of water in the soil relative to the volume. To calculate it, the sensor measures in a “sphere of influence” around it, let’s assume it is 1 m³. If the result is VWC = 2%, it means that, out of that cubic meter of soil, 2% is pure water. That is, 2% of 1000 liters, which is .... The capacitive soil moisture sensing probes we supply with our Harvst greenhouses are examples of this and ours measure soil temperature too. Here, measurements are gathered by recording how the soil reacts to an electrical field around the sensor. An accurate and cost-effective option for the average gardener. "/>How soil moisture sensor works