It's a Philly thing, but I'll call it Just A Wood'N Box Of Dirt.
Scrounged up some scrap wood consisting of some 2" thick planks, butcher block, 6" newel post and other wide planks to be assembled with leftover nuts and bolts from treehouse and firewood shelter builds. Gonna be bloody heavy but nice and sturdy (I tend to overbuild).
I have to dig out some storm swales around the property so will dig deep to get some soil clay to fill the box.
Should be around 25" x 35".