Earth-Berm Greenhouse: How It Differs From a Walipini (and When It's the Better Dig)

Quick Answer: An earth-berm greenhouse builds at or near ground level and piles soil against the north wall (sometimes east and west too) for wind-blocking and thermal stability, rather than digging the whole floor below grade the way a walipini does. Real documented builds berm the north wall roughly 6-8 feet tall, pair it with south-facing glazing for low winter sun, and still add water-barrel or stone thermal mass behind the glazing to actually hold heat overnight. It’s a meaningfully smaller earthworks project than a walipini — no deep excavation, no flooding risk from a dug pit — but it also gives up the deep, stable ground temperature that makes a true pit design work, so the trade is less risk for less benefit.

We covered the walipini — the fully sunken pit greenhouse — as its own guide, and the two designs get confused constantly online because both use “earth” and “greenhouse” in the same breath. They’re not interchangeable. A walipini digs the growing floor itself underground; a berm greenhouse stays at grade and banks soil against one or more exterior walls instead. If you’ve been searching either term trying to figure out which one actually fits your site, here’s the real difference, what documented builds have actually cost and looked like, and which problem each design solves.

Earth-berm greenhouses by the numbers:

• 6 feet — the north-wall berm height on a backyard build documented by a Mother Earth News reader in southern Idaho, who glazed the south side with recycled patio doors at roughly $10 each rather than buying new glazing.
• 4-5 feet of south glazing, ~8 feet effective north wall — the dimensions from a Newfoundland passive-house-style build written up on Green Building Advisor, where the earth berm on the north side brings the back wall’s effective height well above the glazed front.
• 16 by 16 feet — the growing-space footprint of an earth-sheltered build based on Mike Oehler’s plans and documented by Mother Earth News, sited into an existing south-facing hill rather than a flat lot.

1. The real difference between a berm and a walipini

A walipini excavates the growing floor itself 6-8 feet down, so the whole space sits surrounded by soil on every side except the low, angled roof. A berm greenhouse does something much smaller: the floor stays at or near existing grade, and soil gets piled up against the outside of the north wall (and sometimes the side walls) while the south wall stays glazed and above ground. You’re not digging a hole to build inside of — you’re adding an earthen wind-and-cold barrier to one side of a structure that otherwise looks like a conventional lean-to or A-frame greenhouse.

That distinction matters for site selection. A walipini needs a spot where you’re comfortable excavating 6-8 feet down and dealing with whatever water table and soil type you find there. A berm greenhouse works best built into an existing south-facing slope — several documented builds, including the Mike Oehler-plan build above, specifically use an existing hillside so the berm is partly already there rather than entirely trucked-in or hand-piled fill.

2. What a real berm build actually involves

The core recipe across documented builds is consistent: south-facing glazing sized to catch low winter sun, heavily insulated or earth-bermed north/east/west walls that don’t need to be transparent, and a berm height tall enough to actually block wind at the back of the structure rather than just decorate the foundation. The southern Idaho reader build bermed the north wall to 6 feet and reused recycled patio doors for glazing instead of buying new units — a detail worth copying if you’re trying to keep cost down, since glazing is usually the single most expensive line item on either a berm or a walipini build.

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Soil alone, even piled several feet thick, is a mediocre insulator — the real benefit of a berm is blocking wind chill and smoothing out air-temperature swings at the back wall, not actively radiating heat into the space. Every documented build that performs well through a real winter adds separate thermal mass inside, behind the south glazing:

3. Which risk you’re actually trading away

That’s the real trade. A walipini gets more thermal benefit from the ground because the whole growing floor sits inside it, but it also inherits the ground’s biggest liability — water has to go somewhere, and a dug pit is the lowest point on the lot by design. A berm greenhouse gives up some of that deep-soil stability in exchange for a dramatically lower-risk, lower-labor build: you’re not excavating a hole that can flood, you’re adding an earthen windbreak to a structure that still drains like any normal at-grade building.

4. Which one actually fits your site

If you have an existing south-facing slope, a berm greenhouse is usually the more practical build — you’re working with the land’s natural grade rather than fighting it, and site prep is closer to what one of our reviewed walk-in kits needs than to a multi-day dig. If your lot is flat and you’re specifically chasing the deepest possible thermal stability for true year-round growing in a cold climate, the walipini’s full excavation is doing a job a berm alone can’t replicate — see our walipini greenhouse guide for the drainage work that design demands in return.

Neither design is a substitute for checking your local frost depth, water table, and permit rules before moving any earth. If a flat lot and no interest in an earthworks project describes you better, our best greenhouse kit roundup and greenhouse foundation guide cover the above-ground route that gets real frost protection without digging or berming anything — our recycled window greenhouse guide covers a third above-ground DIY option built from salvaged materials instead of a kit.

How to decide

• Have an existing south-facing slope? A berm greenhouse uses it directly and needs far less earthwork than starting from flat ground.
• Chasing maximum winter thermal stability on a flat lot? That’s the walipini’s job, not a berm’s — budget for its drainage work too.
• Either design still needs separate thermal mass — water barrels or stone — behind the glazing. Soil alone, piled or dug, isn’t enough on its own in a real winter.
• Insulate the earth-contact wall with closed-cell rigid foam, not a product meant for glazing, since it’s sitting against damp soil long-term.

The bottom line

An earth-berm greenhouse and a walipini both use soil as part of the design, but they solve different problems: a berm blocks wind and adds modest stability to an otherwise conventional above-ground structure, while a walipini commits to full excavation for a much bigger thermal-stability payoff and a much bigger flooding risk in return. Pick based on your actual site — slope versus flat ground — rather than the design that happens to go viral first, and plan the thermal mass and drainage work either one needs before you move any earth. If digging or berming earth isn’t an option at all, a recycled window greenhouse is the above-ground DIY alternative — just budget realistically, the same way you should for a shipping container greenhouse, which costs far more than either earthwork option despite sounding like a shortcut.