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.
Use your recycled bottles with Aqua Cones to keep your plants and flowers watered. Aqua Cones work with any soil type because they were designed with punch-out holes near the top for sandy. -where the hell do I find an acqua cone?