SparkFun Moisture Sensor

Hi,

I have a SparkFun Soil Moisture Sensor connected to a Picaxe:

high EnableSensor

pause 4000

readadc10 B.1 Value

low EnableSensor

The sensor was planted in a wet pot more than a week ago together with an unpowered sensor with a scale from 0 to 10 and the SparkFun sensor showed Value = ~871 and the unpowered sensor showed ~6.

Now, more than a week later, they show respectively ~471 and ~1.

If I pull the SparkFun sensor out in the air it shows ~0.

Why does the SparkFun sensor not come down when it is in the pot?

best regards

torben