My roommate's classmate gave me this box. It originally had a window on top so it could be used as a seedling greenhouse. He neglected to mention that the window was missing so I decided to turn it into a wee planter box.
I put a double layer of window screening in the bottom . . .
I filled it with soil . . .
And I planted my lettuce.
There was an article a couple years back, I swear it was in the NY Times though I can't find it now, that said lettuce only needs a few inches of soil. I usually grow ten times as much lettuce as this; I love a big salad and homegrown lettuce tastes soooo much better than store-bought. If this plot thrives in the shade of the garage I may build another bed. And another one for arugula. And another one for radicchio! Yum.