Auto-watering wifi, need advice

Hey everyone.

Im in the situation, that i can only check my plants once or twice a week, so i need to make some kind of auto-watering device.

I do have the sonoff 3g/4g that i can turn on and off whenever needed, so i need some device that can water my plant when given power. I only need to water 2x11l pots.

Any advice, or inspiration?
Thanks!

A 50gal reservoir, a small 150gph or so pump to always mix it, another pump adequately sized for your application depending on plant size and how many, a simple manifold that's as long as need be, then branch off with individual irrigation lines.
You know how sprinklers work in peoples lawns right? This is the same concept, No different, man.