What is a pH Meter?

A frequently asked question is: "What is a pH meter?"

Soil acidity (and acidity of any substance) is expressed as 'pH' and so a 'pH meter' is simply a meter that shows you the acidity of your soil in an easy to read way. The pH meters we are talking about here are electronic devices that measure the very small electrical voltage in the soil to indicate the pH.

Specifically, a meter will be attached to a probe, the end of which is a thin glass bulb. The small voltage (about 0.06 volts per unit of pH) is then measured to indicate soil activity in the form of positive hydrogen ions, also known as 'cations'. ('Cations' are attracted to cathodes, 'anions' to anodes.) This is probably more than you need to know, but for more scientific detail still, visit the article on Wikipedia.


The benefits of a pH meter over testing kits and lab tests are that you can use the meter as many times as you want or need to, and get instant results. An electronic pH test meter will give you consistent and reliable readings, although it should be calibrated regularly as the probe itself will change in character over time. For this reason a pH meter should be recalibrated at the start of each working day it's in use. This is simply done by immersing the probe tip in two substances - buffer solutions - each with a known pH, usually at the extremes of the pH you are likely to measure, say 4.0 and 10.0.

The probe will also need to be cleaned at intervals in distilled water and less frequently with  a more powerful cleaner such as a hydrochloric acid solution.

Precise instructions on calibrating, maintaining and using your pH meter should be included with the equipment itself.

You will find a good range of pH meters at Novanna Measurement Systems website, at prices that reflect the savings to be had by obtaining them directly from the manufacturers.

Soil Testing Kits and Equipment

On this blog we will be bringing you news and information about soil testing kits, equipment and systems, advice about choosing the best equipment for your needs and instructions about how to use it.

For soil testing and other test and control equipment, visit Novanna.co.uk and for other news about agricultural testing, meteorology and more, visit agricultural-measurement.blogspot.co.uk