In the mid '70s I ran an interior plantscaping company in Los Angeles. That was when I discovered sub-irrigation (aka self-watering) planters and systems. This is one of the systems we used. It is called the Mona Plant System (MPS) and was invented in Sweden. Back then, it was already a well-established system in Europe.
The MONA tank on the left can be installed in any watertight planter as shown in the cross section on the right. The tank holds water poured into the fill tube. The cone in the center creates a soil wick that moves water up into the root zone by capillary action. The soil wick used here is the same technique as used in the EarthBox.
It is rather amusing to read about “new technology” or “new systems” when reading about self-watering planters such as the EarthBox. As the MPS illustrates, these systems and planters have been around for at least forty years, perhaps longer. The MONA company is no longer in existence but the system is still around.
The MONA system is quite flexible and there are many components for both freestanding planters and planter beds. They are available in Europe and you can see them here.
Click on the item to see a photo of it.
Sub-irrigated grow boxes and other planters are still a big mystery to most of our horticultural and gardening institutions. The current buzz about local food and urban agriculture, however, is slowly opening some long closed minds. In my view it is a national disgrace that it has taken us this long and we still have a long way to go.