@peekay123, Thanks for responding, in Japan so off by 13 hours this week.
@RWB, It would be great to have you implement this project, I am sure you could make some great suggestions for improvement and I would like to see what the Losant Platform brings.
I used Plasticote to spray the probe as it is waterproof but it can also be peeled off if you make a mistake (and I make a lot of mistakes). I may look for something better next season but it is working very well for now and does not impact the sensitivity of the problem much at all. This is the advantage of the capacitive soil sensor - no metal contacting the soil.
As for plant safe - um not sure there. Once it dries, I can't imagine there being much interaction with the soil.
I will likely lay out a PCB for this in the next week or so. I will get three from OSHPark and would be happy to send you one for free. Would love to get more input for improvements.
Also, I plan to do some more Webhook work on this one - need to move away from the JSON approach and start using BODY from the command line as sending the "context" such as "NOT NEEDED" when each watering value is assigned is beyond what a JSON web hook can handle. Not sure if the Losant platform can solve this as it seems to be a Particle Webhook limitation.