Building a hillside root cellar for under $800

A root cellar is a hole that does not flood, freeze, or cook. That is the whole specification. I built this one into a north-facing bank behind the shop for less than eight hundred dollars in materials because I already had a shovel and a week of evenings.

The hole

Eight feet wide, ten feet deep, six and a half feet of headroom. I sloped the floor a quarter inch per foot to a four-inch drain tile that daylights downhill. If you cannot drain it, do not build it. A wet cellar is a mushroom farm.

The shell

Concrete block on a poured footing, two courses below grade. I parged the outside, stuck on two inches of rigid foam, and backfilled with the soil I took out. The door is a reused solid-core with weatherstrip and a second storm door for an airlock. Two four-inch vents: one low, one high, screened, with blast gates so I can slow the air in January.

What lives in it

Potatoes and carrots in crates, onions and garlic up high where it is drier, squash on open shelves, canned goods on the back wall. A twenty-dollar min-max thermometer told me more than any book. First winter it sat between 38 and 52. I closed the low vent in the deep freeze and it stopped flirting with 34.

What I would skip

A fancy arched brick face. It photographs well and costs more than the shelves. Spend the money on drainage stone and a door that actually latches from the inside.

If you rent or cannot dig, a buried chest freezer with the seal pulled and a couple of vent pipes will hold carrots through March. Same physics. Smaller hole.