Soil moisture

I want to measure the amount or level of moisture in dirt. This will be a long term system, so don't want to use the normal conductivity system because of plating or build-up on the electrodes. Thinking about using the capacity measuring type of sensors/monitors. In reading many articles there are numerous methods and frequencies suggested. My question: Anybody have knowledge and experience on doing this, and what are some ideas, suggestions, and/or best way to think about? What worked for you, and any thoughts?

Also thinking about using conductivity, and by using a pulse with very low duty cycle would minimize the plating action. But wouldn't I still have some corrosion build up just due to the probes sitting in moist dirt?

Thanks

 

Thanks, Bluejets. With the probes like you mentioned, there still would be corrosion after sitting there for months on end, I think. With the caps connected to the probes, that way, at least problems from DC current causing plating, would be stopped. I'm thinking I could build my own probes, and stay analog all the way. I would like the info. to read out on a meter and also trip a relay. That part is simple. I am just scratching my head on the sensor/probe part.