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Betting On Geothermally Heated Greenhouses, Iceland Already Produces 70% Of The Tomatoes And Almost 100% Of The Cucumbers It Consumes, Cuts Imports From Europe, And Is Also Testing Banana And Cocoa As A Showcase For Sustainable Agriculture In Extreme Climate.
What seems impossible on climate maps is becoming routine in the Atlantic Arctic. With geothermally heated greenhouses, a country of cold summers and dark winters is showing that vegetables, fruits, and even tropical crops can thrive inside glass structures heated by water that boils from the ground. Today, a large part of the tomatoes, cucumbers, and fresh greens that reach Icelandic tables are grown locally, reducing trucks, ships, and dependency on imported vegetables from Spain and the Netherlands.
At the same time, families, small producers, and researchers are exploring different paths using or dispensing with geothermally heated greenhouses. On one side, farms channeling volcanic heat to produce year-round. On the other, projects like Hildur’s, in the frozen fjords, proving that it is possible to harvest roots, greens, and even sour fruits in cold greenhouses, simply by fine-tuning management and respecting the rhythm of the seasons.
A Country Where The Heat Comes From The Ground, Not The Sky
Growing vegetables outdoors in Iceland is almost impossible. Even in August, the thermometer barely exceeds 12 degrees, and the weather changes rapidly.
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The sugar-energy sector advances with agricultural technology, but agricultural productivity still raises concerns.
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The eggshell that almost everyone throws away is made up of about 95% calcium carbonate and can help enrich the soil when crushed, slowly releasing nutrients and being reused in home gardens and vegetable patches.
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The water that almost everyone throws away after cooking potatoes carries nutrients released during the preparation and can be reused to help in the development of plants when used correctly at the base of gardens and pots, at no additional cost and without changing the routine.
But underfoot, the reality is different: the volcanic island sits atop a massive reservoir of heat, which emerges from deep wells as boiling water.
Today, about 90% of the country’s homes use urban heating with geothermal water, and the same energy network powers geothermally heated greenhouses in the southwestern part of the island.
The logic is simple and powerful. The hot water pumped from the ground circulates through pipes in the floor or walls of the greenhouses, maintaining a temperature of around 20 degrees and creating an “artificial summer” in the midst of cold, windy fields.
It is this constant heat that allows Iceland to produce about 70% of the tomatoes it consumes and almost 100% of the cucumbers indoors, under glass, with geothermally heated greenhouses.
Direct result: fewer containers of vegetables crossing the Atlantic, more food security, and more income circulating within the territory.
Geothermally Heated Greenhouses: Icelandic Tomatoes With A Taste Of Childhood
Near Reykjavik, Thomas’s family transformed a 100-square-meter area into a small vegetable paradise. Outside, cold wind and 12 degrees.
Inside, thanks to the geothermally heated greenhouses, the thermometer reads a comfortable 20 degrees, and tomato plants climb to the ceiling heavy with colorful fruits.
Thomas, a software developer by profession, decided to return to the family’s old property to recover the flavors of his childhood.
At first, he tried common seeds bought in Iceland. The taste was nowhere near what he remembered.
So, he began a quest for old and native varieties worldwide until he found tomatoes that delivered acidity, sweetness, and aroma similar to those from his childhood.
Today, he cultivates more than 30 types of tomatoes and uses the geothermally heated greenhouses to extend the season from May to November, harvesting cherry tomatoes, elongated ones, large, striped, and in various colors.
The routine has become part of the family’s life. His wife and son help with the harvest, and their favorite dish is simple and flawless: pasta with fresh tomatoes straight from the greenhouse, garlic, basil, and greens harvested just hours before.
For them, the impact is concrete. It’s very different to open a supermarket package and instead cook with something you saw grow, pruned, watered, and harvested.
Geothermally heated greenhouses, in this case, are not just technology: they are a way to reconnect with flavor and memory.
From Tomato To Cocoa: When Geothermal Energy Creates “Tropics” In The Arctic
The same logic of geothermally heated greenhouses that makes tomato and cucumber production viable has opened space for even bolder experiments.
At the Agricultural University of Iceland, researchers have been testing for decades what geothermal energy allows planting so far north.
Inside an experimental greenhouse heated year-round by hot water pipes, the northernmost banana plantation on the planet grows, maintained at around 20 degrees.
The plants bloom, form bunches, and produce fruits that feed the university itself, but the verdict is harsh: with dark days, no artificial light, and long maturation time, cultivation does not pay off at a commercial scale.
Even so, the results are symbolic. The 50 banana plants show how far the combination of geothermally heated greenhouses and careful management can go.
Next to them, another star catches attention. After more than ten years of attempts, researchers harvested the second cocoa pod fully produced in Iceland.
From the first pod, only 13 seeds emerged, enough for a single bar of Icelandic chocolate. The second capsule already came with more than 20 seeds, a small leap for the lab but a huge symbol of the possibilities opened by geothermal energy.
There is no Icelandic cocoa in supermarkets, and researchers know that. The goal is not to become an exporter of chocolate, but to show that in a country with cold, wind, and little light, the right technology allows testing limits, diversifying agricultural knowledge, and inspiring solutions for cold regions on other continents.
When The Greenhouse Is Not Heated: Agriculture At The Limit Of The Fjord
While geothermally heated greenhouses dominate the southwest, there are regions in Iceland where subterranean heat simply does not reach.
In the more isolated and colder western fjords, Hildur decided to take the opposite approach. Instead of seeking hot water pipes, she chose to cultivate in cold greenhouses, without heating, relying only on weak sunlight, management, and creativity.
A landscape architect by training, Hildur refuses to rely solely on supermarket vegetables. In the summer months, she moves with her family to a dome-shaped house that mixes living space and greenhouse.
There, she uses sheep wool to protect roots from the cold, applies permaculture principles, and takes advantage of every ray of sunshine to bring beets, pumpkins, zucchinis, and greens to the kitchen.
On the slopes of the fjords, she also maintains a terrace garden, where she grows cabbages and cold-resistant roots, as well as strawberries that sometimes do not even turn red but remain edible, sour, and surprising.
Hildur’s thesis is simple and powerful: it is not impossible to grow vegetables outdoors in Iceland; it just requires more patience, observation, and respect for the rhythm of the seasons.
For her, geothermally heated greenhouses are an important option for the country, but not the only answer.
Hildur prefers to reduce energy use, make her compost, save seeds, avoid artificial fertilizers, and show that even without heat from beneath the earth, it is possible to move towards self-sufficiency.
Local Food, Shared Knowledge, And The Future Of Sustainability
Across the country, the combination of geothermally heated greenhouses, family projects, and university experiments is reshaping the food landscape.
Iceland, which for a long time depended almost entirely on fish, meat, and fermented foods, now sees vegetables, leafy greens, and fruits gaining space on plates and in culinary identity.
Chefs from Reykjavik travel across the island to seek out Thomas’s tomatoes, harvested in the morning and served a few hours later in soups, salads, and elaborate dishes.
Meanwhile, in the fjords, Hildur organizes workshops in her terrace garden, sharing plots with neighbors, teaching them how to plant, care for, and transform harvests into herb salt, sauerkraut, and preserves.
The thread connecting these stories is the idea that access to quality food involves both technology and culture.
Geothermally heated greenhouses reduce imports, cut distances, and help stabilize supply, but alone they do not solve everything.
They work best when coupled with attentive producers, more demanding consumers, and policies that respect environmental limits.
In a small, cold, and isolated country, where heat comes from the ground and not from the climate, Iceland is proving that sustainable agriculture in extreme cold is more than just marketing.
It is the result of an equation between clean energy, patient experimentation, and people willing to rethink their relationship with food.
If every village had its community garden and every region made full use of its geothermally heated greenhouses, the dream of an almost self-sufficient Iceland in vegetables would cease to be a utopia and become strategic planning.
In the end, the “vegetal miracle” of Iceland is not just in the geothermally heated greenhouses but in the willingness to use this resource carefully and recover the knowledge that, as Hildur reminds us, has existed since the Viking era.
And you, looking at the climate and reality of your region, do you believe that geothermally heated greenhouses or other local solutions could really change the way your city produces and consumes fresh food?
Iceland and The Future of good Production controlled By Technology . A Islândia usa tecnologia e recursos naturais disponíveis para superar os limites climáticos na produção agrícola.