Arduino Plant hidration system

I always wanted to have my small garden on balcony, but hot summer, my lazyness and lack of knowledge about gardening whatsoever were reasons why I didn’t have proper one. My wife is better in that part, but lack of time drove her off that garden. So I decided to make my own watering system. It’s isn’t much for now, for one (bigger) pot, but it will expand later. This easy, small system is made of one Arduino Nano (clone, I guess, having in mind the price), one 3.3v relay, 12v self-priming pump, soil humidity sensor, two power supplies (5V for Nano and 12V for pump) and bunch of wires and hoses. And 25 liter canister.”