Depending on what you want to do, maybe you don't need to overcome it. I'm a fan of these, which are "automated", but require no electricity: https://www.blumat.com/classic/uber-classic

I haven't tried these, but they might be more suitable for an outdoor garden, and I've heard good things: https://www.blumat.com/tropf/das-tropf-blumat-system/vorteil...

I think there's a way to hook the latter up to mains water if you have a big install.

Basically, the soil moisture determines the watering rate via diffusion through a clay cone.

I was getting all ready to rig up some custom raspi sensor based watering thing when I found this and realized that my way would have been waayyyy more maintenance headache, more expensive, and probably not work as well.

Yes so it's a Z-Wave valve which has been connected to a split off of the cold water line to my kitchen sink. Typically this valve could be used to control your mains but I'm just using it to feed some drip lines. Basically one small garden and then a few runs to individual planters with an adjustable dripper on the end.

I have automations to limit watering if it has rained recently, and also to increase watering if the day has been extremely hot. Still looking to make it even smarter but this has already been a great improvement.

If it is done with solenoids they can only let water through when there is power applied and the spring should return the stopper whenever there isn't any power.