Garland Products Soil pH Meter

Soil pH Meter

Simple to use, no battery required. Instant acid or alkaline reading.

The meters purely rely on the chemical reaction between the soil and water. To help explain with a bit of science, the meter is an ion meter so it uses two wire coils to measure the electrical potential difference between the two wires. One wire is used for the reading and the other wire is used as the control measure. On a pH meter the electrical potential comes from the soil in the form of hydrogen ions which will act as the electrolyte which is effectively a weak battery. The bigger the difference in voltage between the wires inside, the bigger the difference in hydrogen ion activity between them. If there is more hydrogen ion activity in the test wire, it's more acidic and the meter shows this as a lower pH; in the same way, if there's less hydrogen ion activity in the test wire, the meter shows this as a higher pH (more alkaline).