Brooks-Church has been perfecting the concept of green walls for over 10 years, and he cautions that, “You’ve really got to know what you’re doing to install a good living wall. We’ve gotten it down to a process that is really simple, and once you install it correctly it pretty much takes care of itself.” The first step is to attach a piece plywood to the wall that is covered by a sheet of plastic for waterproofing. On top of that is a layer of ground-up coconut coir. This is the hard inner part of a coconut that is excellent for retaining water. The plants are inserted into pockets in the coconut coir, and an irrigation system drains to the bottom of the green wall where the water can empty into the sewer drain.