Irrigation
Bill McDonald
Do not buy from a big box store. The price is high and some parts are not interchangeable with other suppliers.
I use Ewing Irrigation in San Carlos on Bransten near Industrial.
I use emitters that I call umbrellas. They come in various spread diameters. I use 360 degree emitters that have an additional on off control.
I also have 40 psi reducer to prevent emitter blowouts. Your water pressure should be no more that 40 lbs.
Jerry Carpenter
I have clients that use an automatic system. The name and types are less important than not relying on them. When they go on vacation, they let me know these days because I can check to ensure that:
It is still running
It is adequately watering and not plugged up
The squirrels have not chewed through the drip lines
The power did not go off and the system failed.
etc.
I hand water for a reason. I can control it and know it was done.
Sacramento Bonsai Association https://youtu.be/2Ei2tlKFnw4
Dustin Ho
Check this presentation from Midori https://docs.google.com/presentation/d/18yXCXOE7nWAi3a4STjV_1BmNw_Vo4agDmF5oELLIdKo/edit#slide=id.g131d988a8d2_0_516
Sprayers are generally either uneven or get foliage wet.
No matter what as well, they can be disturbed relatively easily - so you need to check them frequently.
I've tried some options, but concluded the cons outweigh the pros for me with the exception of extremely early prebonsai that I'm willing to lose.
In those cases, I prefer the Netafim sprayers because I find a more even distribution without getting leaves wet.
I think for most bonsai hobbyists, you learn a lot from watering and observing every day, so you may as well water manually.
It's a different story if you're a nursery professional or bonsai professional who uses automatic watering to augment your schedule.
For vacations, I've leaned on neighbors and bonsai friends for help. Happy to trade vacation watering sometime if needed.