Gikfun Soil Moisture Kit (EK1915)

I purchased this kit to learn how to integrate a soil moisture detection circuit with a watering pump mechanism.  This kit works however I have the following criticisms:

• It came with no instructions
• The one schematic on amazon is incorrect
• There is no arduino involved (contrary to the description)

Nonetheless, through some experimentation, the following is the schematic setup that worked for me.

 Below you can see the range of analog values read from the moisture sensor circuit.  The low values are when the sensor is dipped into a cup of water.