I bought this one in the spring and discovered that we were watering potted plants too often. We've all heard the mantra about "potted plants need watering several times a day in hot weather...." Some with a LOT of foliage maybe, the majority don't.

Beauty of this is, there is no battery, it IS the battery, the probe is copper and lead and the soil moisture is the elctrolyte. The only maintenance is occasionally cleaning the probe with a brillo pad or equivalent.

Good luck,

Ev

Here is a link that might be useful: Moisture Sensor