Around 40 years of one couple’s off-grid homestead written up project by project — root cellar, rainwater catchment, self-heating greenhouse, coop and hive — as things they built and then had to keep working.
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See what’s inside →An above ground root cellar is what you build when the ground says no. High water table, ledge rock two feet down, a slab-on-grade house with no basement, a rental, or a lot where excavation costs more than the harvest is worth — all of these end the digging conversation, and none of them end the storage one.
What you lose by staying above grade
A buried cellar borrows two things from the soil: stable temperature and free humidity. Earth a few feet down barely notices a cold snap, and it is permanently damp, which is exactly what carrots and cabbage want. Build the same room on top of the ground and you lose both at once. The room now follows the weather with only a day or two of lag, and it is bone dry.
So an above-ground design substitutes for both. Insulation replaces the depth of soil. Deliberate thermal mass replaces the soil’s inertia. And a water source inside replaces the damp earth. Every workable design below is some combination of those three substitutions.
The options, ranked by effort
| Approach | Realistic temperature | Effort | Best for |
|---|---|---|---|
| Unheated interior room (north wall) | 40-55°F | Low | Squash, onions, apples short-term |
| Insulated box in an unheated garage | 35-50°F | Low | Small quantities, mild winters |
| Earth-bermed shed | 34-45°F | High | Full root crop storage |
| Sunken barrel or can | 34-42°F | Medium | A single crop, no daily access |
| Straw-covered clamp | 32-40°F | Low | Bulk roots, one-time opening |
Two of those deserve explaining, because they are the ones people have not heard of.
A clamp is the old field method: a cone of roots on a bed of straw, covered with more straw and then a layer of soil, with a small straw chimney at the top to let heat out. It costs nothing, it holds temperature remarkably well under snow, and its flaw is that opening it partially exposes the whole pile. It works best as several small clamps rather than one big one, each opened and emptied in a single go.
A sunken barrel — a food-grade drum or a galvanized trash can buried to its rim with a straw-topped lid — is technically a hole, but a two-foot one you can dig with a shovel in an afternoon even in mediocre ground. It holds one crop well and is a genuinely good answer for a household that wants 100 pounds of carrots and not a building project.
The earth-bermed shed, done properly
This is the real above-ground cellar: a small structure on the north or east side of the house or a slope, with soil pushed up against three walls and over the roof if the structure can carry it. Even two or three feet of berm buys most of the stability of a dug cellar without a hole.
- Insulate hard. R-20 or better in the walls, R-30 or better overhead. On an above-grade build, insulation is doing the job dirt would have done, and it is cheaper than dirt to add.
- Waterproof before you berm. Soil against an unprotected wall is a permanent moisture source on the wrong side. Membrane, then drainage board, then dirt, and a swale or drain so runoff goes around rather than through.
- Keep the floor uninsulated. A gravel or bare-earth floor is your one direct connection to ground temperature and to free humidity. Insulating it throws away the best feature you have.
- Face the door north. A south-facing door on a small structure loads it with sun every clear winter afternoon, and there is not enough mass to absorb it.
- Vent it exactly like a buried cellar. Intake low, exhaust high, diagonally apart, dampers on the inside. The physics is unchanged — the two-pipe arrangement is if anything more important here, because you will be charging the room with cold air deliberately.
Freezing is your problem now, not warmth
Underground cellars struggle to get cold enough. Above-ground rooms swing the other way and freeze, and a hard freeze ruins potatoes and splits roots in one night. Three defenses, in the order I would apply them.
Thermal mass. Fill five-gallon jugs with water and stack them along the inside walls. Water holds a great deal of heat per degree, and — this is the useful part — it releases a large amount of latent heat while freezing, so the jugs hold the room near 32°F for a long stretch before anything else in it can freeze. They are a battery that discharges precisely when you need it. Twenty jugs is not excessive in a small room, and jugs you have to replace anyway are free thermal mass. Keep them well away from becoming your drinking supply, and see how to prepare water containers if you want them to do both jobs.
Damper discipline. Close the intake down in a cold snap. Most above-ground freezes happen because vents were left wide open from the fall charging season.
A trickle of heat, thermostatically controlled. In a hard climate a small electric source on a thermostat set around 35-38°F — a seedling mat, a low-wattage bulb in a fixture, a small ceramic heater — is the honest answer. It draws almost nothing because it only runs on the coldest nights, and it converts a room that fails in February into one that works.
Safety: Never use a propane, kerosene or any other unvented combustion heater in a small, closed, insulated storage room. Burning fuel in a sealed space produces carbon monoxide, and a root cellar is deliberately built to exchange air slowly. If you need heat in there, it has to be electric — and any fixture near straw or wood shavings needs a guard and clearance.
Getting the humidity back
An insulated above-ground room with a wood or concrete floor will sit in the 50s for relative humidity, and carrots go rubbery in a month at that level. You are adding moisture rather than fighting it, which is the reverse of the usual root cellar advice.
- Pack roots in damp sand, sawdust or wood shavings in bins or crates. This is the single most effective fix and it also buffers temperature.
- Keep a gravel floor and wet it periodically, or set out open pans of water.
- Store the crops that want it dry — onions, garlic, squash — on a separate shelf or in a different room entirely.
- Hang a hygrometer and aim for 85-95 percent for roots. You will be surprised how much water it takes.
What I would build, in order
Start with what you already have. Measure the coldest corner of your house, garage or unheated porch through one winter before building anything, exactly as you would when assessing a basement corner. A great many people discover they already own a 40°F space and just never put a thermometer in it.
If that comes up short, dig two sunken barrels for roots this year — a Saturday and about $60 — and put the squash and onions on a shelf in the coolest interior closet. Only if you are storing hundreds of pounds annually does an earth-bermed shed pay for itself, and at that point you are looking at a small building with a membrane, a berm and a drainage plan. Accounts like the one in The Self-Sufficient Backyard are worth reading first, with the caveat that it is a homestead memoir with build details rather than an engineered plan set — the value is in what needed fixing after the first winter, which is the part no drawing shows you.
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Frequently Asked Questions
Can an above ground root cellar work in a cold climate?
Yes, and cold climates are where it works best — there is plenty of cold to capture. The design problem is preventing freezing, not achieving cold, which is why insulation and thermal mass matter more than in a buried build.
Will a garage work as a root cellar?
An unheated detached garage often has the right temperature range for part of the winter. An attached garage usually does not, because it picks up house heat. In either case, do not store food near stored gasoline, engines or pesticides — plastics absorb fumes.
How much does an above ground root cellar cost?
A sunken barrel is under $100 at the time of writing. Insulating and venting an existing shed or garage corner runs a few hundred in materials. A purpose-built earth-bermed structure is a small construction project and should be budgeted like one.
How long do vegetables keep in an above ground cellar?
Somewhat less than in a buried one, because temperatures swing more. Expect roughly three to five months for carrots and beets, four to six for potatoes if you hold 38-40°F, and less for anything that experiences a warm week.
What to Read Next
- Root cellar ventilation: two pipes, done right
- The root cellar: what it is and who can have one
- How to keep pipes from freezing without heat
- The Food Storage hub
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