Since live plant walls seem to be the latest rage, I thought it might be helpful to actually break one down a bit and show how the whole thing works.
It’s a pretty simple but ingenious system. The plants rest on long trays with a divot at the bottom, and the pots fit snugly in these divots to keep them in place. As water gets pumped from a resevoir below, it cascades through each tray until that tray is filled, then it moves to the next tray down. The bottom tray feeds directly back into the resevoir stowed out of site in the cabinet below.
This way the plants always have enough water without actually having their roots get rot by constantly being inundated. You can even put the pump on a timer so that it comes on at the needed watering interval. This will depend greatly on where the wall is placed, how dry the room is, etc.