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.
I always seem to have a ton of excess rain water in my yard. i think i am going to make two of these Rain barrels. Note spigot on bottom, overflow valve on top. 20 Insanely Clever Gardening Tips And Ideas