I had good results with using a simple timer board that switched the pump on and off at fixed intervals. The total setup (for 5 potted plants) costed around $25

I had good results with using a simple timer board that switched the pump on and off at fixed intervals. The total setup (for 5 potted plants) costed around $25 including the timer board. The results were great especially with tomato and okra where we had a hard time collecting the produce :) Edit: Was using something similar to this board: http://www.ebay.com/itm/Automation-DC-12V-LED-Display-Digital-Delay-Timer-Control-Switch-Relay-A7Y6-/272702855151?_trksid=p2349526.m2548.l4275 http://www.ebay.com/itm/Automation-DC-12V-LED-Display-Digita... I think RPi is a overkill for this project.