Building a planter box against a wall with above-ground footing

Question

I am trying to build a rectangular wooden planter box up against a backyard wall, but the wall's footing is above the ground and differs in height at different points along the wall. The picture below shows the wall footing.

The left side of the footing is a whole cinder block higher than it is on the right side (about 6" difference in height).

The planter box will be rectangular and 4-sided. I've thought about raising the ground height of this area until it's above the footing, or cutting the wood to conform to the general shape of the footing, or simply moving the planter box away from the wall far enough to avoid the footing. All of these options have pros and cons.

What's the best way to deal with the issue of the protruding wall footing?

Answer 1

Personally, I'd move the box away from the wall, as wood against concrete/masonry doesn't end well for the wood due to rot. An option that may give you the best of both worlds is to build the back of the planter box a consistent distance from the wall - say, 5 inches (10 cm). Once you've installed the box and leveled it, you can attach a board across the top fo the back of the box, from the box to the wall. it would be a good idea if you could use a rot-resistant wood for the topper. See here for a basic illustration:

In this case, if the wood from the box to the wall begins to rot, it's fairly easy to replace it - instead of replacing the entire back to the planter.