Review on REOTEMP 24 Inch Garden And Compost Moisture Meter, Garden Tool Ideal For Soil, Plant, Farm And Lawn Moisture Testing by Duane Kaul

This moisture meter requires initial calibration. To do that they want you first to calibrate to the desired moisture level of the soil. You are to put the rod into the soil at the desired moisture level and then turn a calibration screw so the needle moves to the middle of the dial (too dry, correct moisture, too moist). If you already know the moisture level you want, then calibration will be simple. If you don't know what the correct moisture level should be, then the meter won't help you. In my opinion, it is difficult to determine if the meter is calibrated accurately.