Question Worth and other watering gurus-

[Tracydr]

Okay. I need some step by step beginner instruction on making an automatic waterimg system for a 40x40 foot garden. Okay,here's the kicker. Rain water needs to be collected from the barn and I'm not sure when I'll have electricity.
Water and electric will eventually be done but not in time for the tomatoes that are in/going in right now. Or,the peppers,beans,melons,corn and squash.