Hi Sean,
My experience:
I have looked a long time for the right sensor to measure the soil moisture in my garden.
I came across e.g.
- the parrot sensor (http://www.parrot.com/de/produkte/flower-power/)
- koubachi sensors (https://www.koubachi.com/)
- eve (together with irrigation controller)
- many more …
In the end these systems used either cloud solutions (which I did not like, I want to keep my data for myself and not open up any ports in my router), were to expensive, or nor long lasting (most of all the “cheap” sensors you can buy (e.g. http://www.exp-tech.de/sparkfun-bodenfeuchtesensor?gclid=CK68j6XeocsCFYIK0wodSNcGGQ).
Thus I decided use an AVR-NET-IO board in combination with a Vegetronix sensor.
This in combination with a small shell script looging in the AVR-NET-IO via telnet provides me the wanted data.
Maybe this helps.
Cheers
Björn