(I call this a "planter" because at one time the building owners constructed about 20 of these square concrete structures and planted mini-palm trees. Naturally they didn't consider how the plants would be watered so all but 3 or 4 of them have died.)
There are three pretty good reasons my enterprise is pointless:
I'm guessing a day or two.
I'm also guessing the next door neighbors won't notice that some of their dirt is missing.