i've seen these before in a shanti town on brazil somewhere..
the area you're going to have issues with is the hole in the ground imo... you would need tons of fresh air intake to stop things like mold and fungus from growing all over your plants...
this season on the moonshiners tv show, these two dudes spent months digging an underground hole so that they could make some moonshine in it.. after the first hard rain, the place nearly collapsed in on itself, then the mold came in..
last episode i saw they have no moved the site out into the woods and gave up on their hole idea.. i'd imagine you'd have very similar results with your idea..