The latest craze in the green gardening market is the self-watering barrel garden. Barrel gardens are easy to make and efficient to use. A drum can hold up to 72 plants, allowing for more food to be harvested at a one time
How to make a Sub-Irrigated Planter. I'm not sure I would use a two liter plastic bottle though. Over time I would fear the plastic breaking down enough to poison the plant. Perhaps a wine bottle instead.