along a similar vein, remember stumbling across an article on a guy container gardening in India – he sunk an additional PVC pipe into the pot and fed it with kitchen scraps allowing the scraps to compost in place
They are called ollas, but it is a method of using a terracotta pot that you fill with water and keep in the dirt by the plants. As the water through osmosis diffuses through the terracotta, the roots will grow around it, creating a method of self-watering.