I was considering a smart garden setup as well. I ended up going with a dumb version that has no dependency on any electrical power: Blumat. They’re from Austria, if i recall correctly. They feed water as the plants consume it.
The Blumat “carrots” are porous and as the soil dries, pressure becomes negative and opens up the switch that controls the feed water line, which then drips water onto the soil until its reached the calibrated moisture level which closes the switch.
Not “self-hosted” in the traditional sense but definitely hosted in the primitive sense.
Me. I can live on that. I would have to change my habits like eating more but that’s something I am willing to change.