@mckynzee - I was being facetious… a sprinkler controller without a moisture sensor is like a home thermostat without a temperature sensor. Open-loop control systems suffer from offset errors, sensitivity to disturbances, and a high reliance on accurate input parameters.
It seems like many other people realize the desire for this:
@johnny2678 says “Incorporating actual soil sensors would be nirvana” in this post.
@azdavidr says “Integrating robust soil moisture sensors seems like the holy grail for smart irrigation as they complete a closed-loop system” in this post.
@franz, @plainsane, @jjpaz and others talk about integrating soil sensors extensively in this thread (Feb 2015 - June 2016).
It seems crazy (to me) that Rachio doesn’t allow the input of soil moisture data.
In the meantime, it seems like the workaround is to disable all schedules on the Rachio and write your own closed-loop control system to trigger individual watering sessions using the soil moisture data.