All soil moisture sensors will eventually become uncalibrated, wear out, or fail.
The only automation you need to keep a plant alive is a timer attached to a water source. Also, don't forget to feed it with nutrients every month or so... they don't eat soil and letting a plant starve isn't proof you needed a moisture sensor.
The only automation you need to keep a plant alive is a timer attached to a water source. Also, don't forget to feed it with nutrients every month or so... they don't eat soil and letting a plant starve isn't proof you needed a moisture sensor.