There are two types of soil testers, the ones that use electricity and those that use light. Electricity-based soil testers emit a high frequency of radio waves that bounce off of the particles in the soil and measure how much energy is returned to the receiver. Light-based soil testers emit light and measure the amount of light reflected back to the receiver.
For soil testing, your best bet is to go with an electricity-based soil tester as it's important to be able to test for electrical conductivity. You need a soil tester that will give you accurate results and not just read the voltage.
An electricity-based soil tester is a device that can help you determine which soil conditions are best for growing your plants. The process involves applying a certain voltage across the soil and measuring the current. It’s important to note that there are different types of soil testers. The idea is that the electrical conductivity of the soil varies with different conditions. For example, sandy soil has high electrical conductivity. When soil is saturated, it’s like a sponge and has low electrical conductivity.
The most popular soil tester is called a “Wet/Dry Meter” or simply a “Wet/Dry Meter” (see our article on How to Buy a Wet/Dry Meter). These are popular because they are easy to use and inexpensive.