Concept 2026 — Helsinki, Finland

Food from within the earth, for the world.

The world's first geothermal spiral garden — quarried deep
into Helsinki's bedrock. Thousands of hectares of cultivated area
without sunlight, without being at the mercy of the weather.

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Why this matters

The world is hungry.
It doesn't have to be.

More than 700 million people are going hungry this year. At the same time, a third of all food produced is thrown away. The problem is not production — the problem is dependence on the weather, fossil fertilisers and fragile supply chains.

Climate change is making things worse. Droughts, floods, heatwaves — conventional agriculture is vulnerable at exactly the moment it is needed most.

The Mesivarpaa solution: take farming underground, where the temperature is stable, water circulates and energy rises from the depths — and crops grow all year round regardless of what happens on the surface.

733M
people going hungry
in the world today
33%
of the world's food
is wasted
+2°C
a temperature rise threatens
to cut harvests by 25%
4800 ha
of cultivated area
in three spirals
Hydroponic lettuce
Fresh farm vegetables
Green growing field
How it works

Three innovations.
One system.

🌀
Geothermal Spiral
The tunnels are quarried to a depth of 2 km at a 1–2% gradient. The spiral shape means that heat rising from the depths is naturally distributed into different zones — from tropical plants to cool-climate vegetables.
8×8M TUNNEL · 1–2% GRADIENT · 100–200 KM OF TUNNEL / SPIRAL
💧
Closed Loop
Water and nutrients are fed in from the top and flow by gravity through the whole spiral. The plants take exactly what they need. At the bottom, the water is cleaned in a collection basin and pumped back up. Nothing is wasted.
HYDROPONICS · 95% LESS WATER THAN CONVENTIONAL FARMING
⚡
Energy Self-Sufficiency
Deep in the bedrock the temperature is +60–70°C. Heat pumps turn it into energy. Grow LEDs in the upper levels are supplemented with sunlight-carrying fibre-optic cables. Goal: a net-zero-energy farming system.
GEOTHERMAL + LED + FIBRE-OPTIC SUNLIGHT · GOAL: NET ZERO
🅿️
Surface Levels
Parking, storage and distribution terminals are located at a depth of 0–50 metres. Cars off the streets, logistics underground. These levels can be partly financed by selling parking spaces.
PARKING · STORAGE · COLD CHAIN · DISTRIBUTION TERMINALS
🤖
Automation
Harvesting, planting, irrigation and nutrient control are carried out by robots. Sensors measure the growth of every plant in real time. Human work shifts to design and development.
ROBOTICS · IOT SENSORS · AI-OPTIMISED GROWTH
🌍
Scalable Model
Helsinki is the prototype. The same concept works anywhere there is bedrock — Scandinavia, Canada, Japan, South Korea. The quarried rock is sold as construction material, which covers part of the costs.
REPLICABLE MODEL · QUARRIED ROCK = CONSTRUCTION MATERIAL
Structural zones

From the surface
to the depths.

0 – 50 m
Surface — Infrastructure
Parking, storage, distribution terminals, cold chain. Cars off the streets, logistics efficiently underground.
+8–12°C · Cold storage
50 – 300 m
Cool zone
Leafy greens, herbs, lettuces, spinach, kale. Northern-climate varieties. LED lighting + fibre optics.
+10–20°C · Herbs, lettuce, leafy greens
300 – 800 m
Temperate zone
Tomatoes, cucumbers, peppers, courgettes, berries. Potatoes and root vegetables in growing beds on the spiral floor.
+20–30°C · Vegetables and fruiting plants
800 – 1400 m
Warm zone
Tropical plants — banana, mango, papaya, ginger. Mushroom cultivation makes efficient use of the heat and humidity.
+30–45°C · Tropical + mushrooms
1400 – 2000 m
Geothermal zone
Heat exchangers, energy production. Hot water is pumped up to heat the upper zones. Nothing is grown here — this is where the energy is made.
+50–70°C · Energy production
HELSINKI · GROUND LEVEL LIFT · PIPES · CABLES 🥬 🌿 🌱 🥦 🍅 🥒 🫑 🍓 🍌 🍄 🫚 🥭 ⚡ GEOTHERMAL ENERGY +60–70°C · 2000m DEPTH 0m 300m 800m 1400m 2000m ↓ ↑

TUNNEL SIZE: 8×8 METRES
GRADIENT: 1–2%
SPIRAL DIAMETER: 500–1500 M
DEPTH: 2000 METRES
TUNNEL PER SPIRAL: 100–200 KM

Dimensions

Numbers speak.

4 800
hectares of cultivated area
in three spirals
2M+
people fed
per year
350 km
of tunnel in total
three spirals
50–100
bn €
total investment
all three spirals

FOR COMPARISON: Olkiluoto 3 nuclear power plant = €11 billion · Helsinki's Länsimetro (western metro extension) = €1.2 billion · Quarried rock (~50–100 million m³) can be sold as construction material → worth €500M–2bn · Parking facilities can be financed by selling parking spaces

Greenhouse interior
Timeline

The path from idea
to reality.

2026–2028 · Now
Concept & Community Building
Publishing the idea and building a community of interested researchers, engineers, investors and policymakers. Commissioning the first technical studies.
2026–2030 · Near future
Prototype — Small pilot at 50m depth
A small pilot tunnel (2 km long) is built at a depth of 50 metres to test the growing system, water circulation, LED lighting and automation. Goal: to prove that the concept works.
2030–2040 · First spiral
Full-scale Spiral I — Helsinki
The first Ø500m spiral down to a depth of 500m. Partly financed by selling parking and storage space. Support from EU food security programmes. Commercial operations begin.
2040–2060 · Expansion
Three Spirals, Full Depth
All three spirals (Ø500m, Ø1000m, Ø1500m) reach a depth of 2 km. Geothermal energy in full use. The system covers the vegetable needs of all of Finland.
2060+ · Global
A Replication Model for the World
The Helsinki model is licensed to other countries. Scandinavia, Canada, Japan, Korea — there is bedrock everywhere. The Mesivarpaa spiral becomes the global standard for food production.
Join us

This idea needs you.

Are you an engineer, a researcher, an investor, a politician — or simply someone who wants to save the world? Everyone is welcome. The idea is open — let's develop it together.

Write to us Read more
Mesivarpaan maanalaiset pellot
Honeytoe's Underground Fields
Helsinki, Finland
teemu@mesivarvas.fi
mesivarvasMade with AI