How to build your own passive hydroponics rig, with just some bottles, soil and cardboard. Full guide for growing your free food - http://red-dot-geek.com/easy-diy-hydroponics-beginners/
Semi-regular Maintenance ⊙ Not a totally hands-free system. ⊙ Still need to top up with water from time-to-time. ⊙ Check if pests are growing inside. ⊙ If root rot (brown slimy roots) happens, quickly remove the plant, and change the water.