Part of building a big planter box is filling it. When you get something as big as we are looking at it can mean a whole lot of dirt. Now we could have put something low to the ground but honestly it is easier to have it high - plus this planter box seconds as a fence for the yard. Thus it is several feet high, lots of dirt.
So to help combat this we have worked to fill about half of the box with rocks and gravel. Going out and finding rocks and gravel can be a big job but also a perfect one to involve little people in. The family that works on yard projects together all enjoy the lawn more later on. At least that can be the hope, right?