2 words - LEATHER PANTS if you think its necessary, ok - 2 layers,,, 1 about 6" off the ground & the other 6" down from the top,,, just be sure they bend around the corners,,, for that size, i wouldn't, tho,,, good luck !
A concrete wall will need a footing for it to sit on, then I'd use 4" concrete blocks not do all the work of forming and trying to pore in that narrow a form.
We buy both full and half blocks and pre lay it out so there's no cutting of the blocks needed.
Ah ****, I already did it. Three walls one solid piece with rebar, no blocks. And no footing!! Joe I don’t think it’s going to move, it is only 2’ high. I did put one foot of gravel under the front if it, that should hold it.