Soil pH meters are devices used to measure the levels of acidity and alkalinity in soil.
The pH meter consists of a probe and an indicator. In order to function, the probe must come into contact with the soil. The indicator will give a pH reading and the result will provide an accurate idea of pH levels in soil for most gardening tasks.
pH is a scale used to categorize substances according to their acid or alkaline properties. There is a bit more to acidity and alkalinity than sourness and bitterness; for more information, see: Wonkee Donkee’s lesson on acidity and alkalinity (pH)
Different plants prefer differing pH conditions for optimal growth and survival, and this is why it may be important to check your soil pH. Soil conditions vary all over the country, ranging from about 4.0-8.5, and can be affected by rainfall, minerals and other plants.
Soil pH meters can have either digital or analogue indicators. Analogue testers will indicate the pH on a scale with a pointing needle, while digital ones will display the pH value on a screen. Digital meters require batteries and are usually supplied with them; analogue meters have an internal battery that cannot be replaced. Other than the display, they function in the same way.