i feel weird about self promoting but I make a project called the Pigrow which is an open source garden automation project designed to be as cheap and flexible as possible by using a raspberry pi and basic components from ebay or wherever. It’s got tools to help you monitor and control the grow environment including various watering tools. It’s not as polished as farmbot but under constant development and having new features added all the time, if you want to set up a cheap irrigation automation system then it might be a good option and if not then i’d love to hear what features it’d need for you to consider using it so i can try and add them. More info at [email protected]