I have two Whisperers that I move around to various parts of my graden to get comparative readings of sunlight and soil moisture.  I really do not know how to interpret the moisture readings which generally range from 50% to 98% but can be as low as 30%.  Soil type varies from a clayey loam to heavy clay.   How do I know when watering is required?  Does the meter measure the capillary water?  The adhered water?  The percentage of voids filled with water?  How does Netro calculate the percentage of water and what do the readings mean?