What Sonnenerde does

Sonnenerde GmbH is an Austrian climate and environmental technology company founded in 1986 and headquartered in Riedlingsdorf, Burgenland. It manufactures over 30 organic soil, substrate, and biochar products sold primarily under the Sonnenerde, Terra Preta, and Kohloss sub-brands. The company operates as a vertically integrated circular-economy platform: it accepts organic waste streams (green waste, sewage sludge, paper fiber sludge, food industry sludge), converts them into premium EBC-AgroOrganic-certified biochar through a proprietary pyrolysis process (the Kohloss plant, opened April 2025), and uses that biochar as the foundation for its soil product line. Its flagship Kohloss facility produces 1,000 tonnes of biochar annually, sequestering up to 2,500 tonnes of CO2, runs at zero external energy via a 3-stage heat cascading system, and yields ~80 tonnes/year of recovered nitrogen as ammonium sulfate. The company also sells CO2 sink certificates generated from the biochar.

Beyond soils, Sonnenerde has built a separate urban infrastructure franchise around the Schwammstadt (Sponge City) Stockholm System, co-developed with the City of Graz and DI Erwin Murer and validated over six years with HBLFA Schönbrunn. This system combines a load-bearing rock skeleton with a biochar-based fine substrate to give urban trees up to 5,000 liters of water storage per tree and a 100+ year lifespan versus 20-30 years in conventional pits. Sonnenerde earns revenue across six streams: soil and substrate products (one-time unit sales, packaged from 12L buckets to Big Bags and bulk), biochar (including fine/ultrafine milled grades for industrial applications), CO2 sink certificates, owned truck delivery services (4-axle trucks up to 14 t and 24 t semi-trailers), waste-processing services, and sewage sludge drying services using Kohloss waste heat. Distribution runs through direct factory sales, a Bloomling.at e-commerce partnership, an Austrian reseller network, and an international B2B biochar channel; brand-building is content-led via the ErdGeflüster YouTube channel (>2M views, >17.7k subscribers) and community events such as Tag der offenen Tür.

Customer segments are horizontal and span home gardeners, professional landscapers and nurseries (Baumschule Loidl, Gartenbayer GmbH, Baumschule Schiller, Gartenfachmarkt Jeitler, Franz Groß), municipalities and city planners (City of Graz, Ökoregion Kaindorf, Tiergarten Schönbrunn), agricultural operators, and cannabis cultivators via the Bio Hanferde Living Soil product. The company is privately held by the Dunst family (Gerald, Regina, Dominik, and Richard Dunst), with no venture capital or private equity backing; CharLine operates as a jointly controlled partner extending biochar into animal husbandry. Key certifications include EBC-AgroOrganic, ÖNORM B 2606-1, Natur im Garten, easy-cert Bio, and Bio Kompost Qualitätsklasse A+, and the firm received the Energy Globe Award 2023 for the Kohloss facility.

Name

Sonnenerde

Legal name

Sonnenerde GmbH

Website

https://sonnenerde.at

Company type

Private

Founded year

1986

Operating status

Operating

Headcount range

11–50 employees

Short description

Sonnenerde GmbH is an Austrian climate tech company that produces over 30 organic soil and biochar products from a vertically integrated pyrolysis and composting operation (Kohloss plant), serving home gardeners, landscapers, municipalities, and agricultural operators across Austria with circular-economy substrates.

Ownership category

akta.pro rank

Product category

Specialty Soils and Biochar

NAICS

Fertilizer and Compost Manufacturing (32531)

SIC

Agricultural Chemicals (2870)

akta.pro primary industry

Biochar & Carbon-Based Soil Conditioners (AFABADAD)

akta.pro secondary industries

Biochar & Carbon-Based Soil Builders (AFABAKAG), Bio-based Fertilizers, Soil Amendments & Biostimulants (Digestate-derived, biochar-based inputs) (EUAAAIAH), Organic & Bio-based Fertilizers (Manure/Compost/Biochar) (IMAEAEAF), On-Farm Circularity & Waste Valorization (Residue Management, Biochar, Manure/Organic Waste Use) (AFAGAMAI), Organics Collection & Processing (Composting/Anaerobic Digestion) (IMAIAFAF), Mulches & Biodegradable Films (Straw, Paper, Bio-based) (AFABAKAI)

Keywords

• Biochar production
• Organic soil substrates
• Pyrolysis technology
• Terra preta amendments
• Sponge city tree planting

Headquarters

HQ city

Riedlingsdorf

HQ country

Austria

HQ region

Europe

Offices1 record

Markets served

GTM type

B2B and B2C

Offering type

Hardware or Manufacturing

Cost components

Supply Chain, Operations, Personnel, Technology or R&D, Marketing or Sales, Infrastructure

Revenue model

1. Soil and Substrate Products: Sale of over 30 different soils and substrates including Bio Schwarzerde, Bio Hanferde, Bio Blumenerde, raised bed soil, seedling soil, and specialty soils. Products sold in various packaging from 12L buckets to Big Bags and bulk orders.
2. Biochar Products: Production and sale of premium biochar (Pflanzenkohle) for agriculture, gardening, and industrial applications. Products include fine and ultrafine milled biochar.
3. CO2 Sink Certificates: Sale of CO2 sink certificates generated from biochar production. The company generates up to 2,000 tonnes of CO2 certificates annually by permanently sequestering carbon in biochar.
4. Truck Delivery Services: Delivery services with their own fleet of 4-axle trucks (up to 14 tonnes each) and semi-trailers (24 tonnes capacity). Delivery charged per hour plus toll.
5. Waste Processing Services: Acceptance and processing of various organic wastes including green waste, sewage sludge, paper fiber sludge, and food industry sludge for composting and biochar production.
6. Sewage Sludge Drying Services: Contract services drying sewage sludge at 300°C using waste heat from pyrolysis process.

Pricing tiers

Go-to-market motion2 records

Distribution channels5 records

Marketing channels9 records

Core offering

Sonnenerde GmbH manufactures and sells over 30 certified organic soil and substrate products, plus premium biochar (Pflanzenkohle) produced at its proprietary Kohloss pyrolysis plant. The portfolio spans home gardening soils (Bio Schwarzerde/Terra Preta, Bio Blumenerde, Bio Hanferde), specialty substrates (raised bed, seedling, herb, tomato, lawn, sports turf, green roof, urban tree), mulches, fertilizers, rock dust, brick chippings, and books. Production is integrated with a circular-economy waste processing service that accepts organic waste, sewage sludge, paper fiber sludge, and food industry sludge for conversion into biochar and compost.

Product overview

Sonnenerde GmbH offers an extensive portfolio of over 30 specialized soil products and growing media, centered on biochar-based Terra Preta technology and organic soil production. The core product line includes premium organic soils (Bio Schwarzerde, Bio Hanferde, Bio Hochbeeterde, Bio Blumenerde), biochar products (Pflanzenkohle, Bodenaktivator, Schwarzerde Konzentrat), mulching materials (Bio Faser), seedling and specialty soils (Bio Anzuchterde, Bio Moorbeeterde, Bio Kräutererde), and urban infrastructure solutions (Stadtbaum Feinsubstrat, Stadtbaum Konzentrat). Supporting products include composts, brick chippings, rock dust, fertilizers, and educational books. The company operates the Kohloss biochar production plant and provides services including composting, truck delivery, and factory sales.

Differentiator

Problem solved

Functional benefit

Brands

• Kohloss: Industrial biochar production facility - one of the most efficient pyrolysis plants in Europe, producing 1,000 tonnes of premium biochar annually with zero external energy required.
• Terra Preta

Products and services

• Bio Schwarzerde (Terra Preta Soil) Premium organic Terra Preta-style soil containing biochar, designed for long-term soil fertility and permanent carbon sequestration in home gardens, raised beds, and ornamental plantings.
• Bio Hanferde (Living Soil) Living Soil substrate for cannabis cultivation, including Cannabis Social Clubs, providing full plant nutrition via biochar-driven Terra Preta effect without additional fertilizer.
• Bio Faser (Bio Fiber Mulch) Dried biogas digestate mulch from organic cattle manure used as long-term nitrogen supplier and soil protection layer.
• Pflanzenkohle (Biochar) EBC-AgroOrganic certified premium biochar produced at 700°C through pyrolysis, used as stable carbon storage and soil amendment for nutrient and water retention.
• Bodenaktivator (Soil Activator) Living soil fertilizer containing activated biochar, rock flour, and microbiology, used to refresh used potting soil and enrich outdoor soils with humus-building properties.
• Bio Hochbeeterde (Raised Bed Soil) Ready-to-use fertile organic soil for raised bed vegetable gardens.
• Bio Blumenerde (Flower Soil) Organic planting soil for flowers in pots and containers, providing season-long nutrient supply with high water retention.
• Bio Anzuchterde (Seedling Soil) Versatile organic seedling soil optimized for use in ball presses, ensuring stable balls with a loose structure.
• Bio Kompost (Organic Compost) 100% mature, 100% plant-compatible organic compost rich in nutrients, suitable for biological agriculture (Quality Class A+).
• Bio Moorbeeterde (Peat-Free Moor Bed Soil) Peat-free Bio Moorbeeterde based on organic compost, ideal for acid-loving plants including blueberries, rhododendrons, and azaleas.
• Schwarzerde Konzentrat (Terra Preta Concentrate) Highly concentrated biochar-mineral complex that upgrades existing soil to Terra Preta quality in a single application without soil replacement.
• Stadtbaum Feinsubstrat (Urban Tree Fine Substrate) Stable planting substrate for urban trees developed with the City of Graz and DI Erwin Murer, consisting of washed quartz sand and urban tree concentrate for the Schwammstadt Stockholm system.
• Stadtbaum Konzentrat (Urban Tree Concentrate) Highly concentrated biochar-based planting concentrate designed for on-site mixing with locally sourced washed quartz sand in Schwammstadt installations.
• Bio Tomaten- und Gemüseerde (Tomato and Vegetable Soil) Nutrient-rich organic soil specifically formulated for tomatoes and vegetables in pots and containers.
• Bio Kräutererde (Herb Soil) Organic soil optimized for herbs in pots, providing ideal growing conditions.
• Bio Toilettenstreu (Organic Toilet Litter) Plant-based organic toilet litter for separation toilets.
• Kompostaktivator (Compost Activator) Compost activator that converts organic waste into high-quality compost.
• Dachgartenerde intensiv (Intensive Green Roof Soil) 100% frost-resistant, permanently permeable substrate for intensive green roof installations with planting depths of 10–50 cm.
• Dachgartenerde extensiv (Extensive Green Roof Soil) Ready-to-use soil for extensive green roofs applied at 8 cm layer thickness, suitable for sedum species and dry grasses.
• Sportrasenerde (Sports Turf Soil) Standardized ready-mixed sports turf base layer compliant with ÖNORM B 2606-1, produced with defined raw materials.
• Sanierungserde (Remediation Soil) Soil for improvement and aeration of compacted areas, ideal for sanding and overseeding after scarification.
• Rasengittererde (Lawn Grid Soil) Structure-stable soil mixture for green driveways using lawn grid stones, featuring high permeability with water storage capacity.
• Rasenerde (Lawn Soil) Freshly sieved soil for home garden lawns.
• Wiesenhumus (Meadow Humus) Humus soil perfect for planting and landscaping applications.
• Bio Teicherde (Organic Pond Soil) Phosphorus-free substrate with low nutrient content, stable and heavier than water, suitable for pond plantings.
• Kompost (Compost) 100% mature compost rich in nutrients, suitable for garden design applications.
• Sonnenstreu (Horse Bedding) Ready-to-use bedding for horse stables for odor binding and stable hygiene.
• Steinmehl (Rock Dust) Silicate rock flour from Aspanger Bergbau (Aspolit) used as a key composting additive and soil amendment with particle sizes mostly under 10 µm.
• Ziegelsplitt (Brick Chippings) 100% frost-resistant crushed brick from roof tile production waste and old clay roof tiles, offered in various grain sizes from 0–2 mm to 8–12 mm.
• Tennissand (Tennis Sand) Pure, 100% frost-resistant tennis sand with a distinctive red color used for tennis court remediation.
• Sulfocarb (Carbon-Sulfur Fertilizer) Novel carbon-sulfur fertilizer using activated biochar from biogas desulfurization, providing sulfur effectiveness and stable carbon for humus building.
• Humusaufbau Book (2nd Expanded Edition) Book by Gerald Dunst on soil as carbon storage, presenting humus building as an opportunity for agriculture and climate (2nd expanded edition).
• Kompostierung und Erdenherstellung Book Practical guide by Gerald Dunst for composting and soil production, aimed at home gardeners, agriculture, municipalities, and professionals.
• Das große Boden-ABC Book Book by ORF gardener Angelika Ertl on ecological gardening, sharing secrets for healthy soils in natural cycles.
• CO2 Sink Certificates Carbon sink certificates generated from permanent CO2 sequestration in Kohloss biochar, marketed to companies and organizations for climate-offset purposes (up to 2,000 tonnes/year).
• Organic Waste Processing Service Contract service accepting and processing organic waste streams including green waste, sewage sludge, paper fiber sludge, and food industry sludge for conversion into compost and biochar.
• Truck Delivery Service Delivery service using Sonnenerde's own truck fleet (4-axle trucks up to 14 tonnes, semi-trailers up to 24 tonnes) with crane unloading over fences up to 15 metres; charged per hour plus toll.
• Sewage Sludge Drying Service Contract service drying sewage sludge at 300°C using waste heat from the Kohloss pyrolysis process, with up to 10,000 tonnes/year capacity.

Quantifiable outcome

• Each urban tree stores 5,000 liters of water and can cool surroundings by up to 10°C
• +5 more outcomes

Named customers10 records

Segments5 records

Ideal customer profiles5 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Integration1 record

Feature7 records

Partnerships

Six partnerships are on record, tiered core.

• CharLinecoreStrategic or Co-development PartnerPartner company producing FeedChar (feed charcoal) and ManureChar (organic manure charcoal) products for direct application in animal husbandry. Sonnenerde provides biochar while CharLine handles the animal health product line. Together they close the circular economy loop: biochar fed to animals binds toxins, later the nutrient-rich biochar in manure improves soil fertility.
• City of GrazcoreStrategic or Co-development PartnerJoint development of the Stadtbaum-Feinsubstrat (urban tree fine substrate) for the Schwammstadt (sponge city) system. The City of Graz was the initial partner in developing this climate-resilient urban tree planting solution.
• DI Erwin MurercoreStrategic or Co-development PartnerCo-developer of the Stadtbaum-Feinsubstrat recipe alongside Sonnenerde and City of Graz. Key technical partner in creating the substrate formulation.
• Ökoregion KaindorfcoreStrategic or Co-development PartnerRegional partnership for comparison planting experiments between natural soil and Stockholm system.验证了 Schwammstadt approach in practical agricultural conditions.
• HBLFA Schönbrunn (Höhere Bundeslehr- und Forschungsanstalt für Gartenbau Schönbrunn)coreStrategic or Co-development PartnerConducted six-year test project with root exposure studies validating the Schwammstadt system's effectiveness. Independent research institution providing scientific credibility.
• NGE (Technology Partner)coreTechnology or IntegrationDeveloped the pyrolysis reactor technology (NGE technology) used in the Kohloss plant. Key technology partner for the proprietary carbonization process.

Scale indicators10 records

Recent moves8 records

Expansion highlights7 records

Direct peers

• Carbofex: Finland-headquartered industrial biochar producer operating one of Europe's largest pyrolysis plants; directly comparable to Sonnenerde's Kohloss facility in end-product (premium EBC-certified biochar) and in serving agricultural and carbon-removal customers across Europe.
• Biochar Supreme: US-based biochar manufacturer with multiple production sites producing EBC/PBC-certified biochar for agriculture and carbon credits; comparable to Sonnenerde as a vertically integrated producer selling bulk and bagged biochar plus blended soil products.
• Carbon Gold Ltd: UK-based biochar company producing biochar-based soil amendments and growing media for horticulture and professional landscaping; highly comparable product/market overlap with Sonnenerde's Bio Schwarzerde and substrate lines.
• Swiss Biochar Sàrl: Switzerland-based biochar producer operating Pyreg/Carbon-Austria-style pyrolysis plants and selling EBC-certified biochar into Swiss and DACH agricultural markets; regional peer with comparable technology and customer profile.

Broad incumbents

• Klasmann-Deilmann: Germany-based global leader in growing media and substrates (including peat-free and biochar-enhanced ranges); competes with Sonnenerde across professional substrates, landscaping soils, and peat-free alternatives across Europe.
• Stender AG: German substrate producer offering professional horticultural soils, lawn substrates, and growing media; overlaps with Sonnenerde's professional gardener segment, especially Rasenerde, Sportrasenerde, and Hochbeeterde categories.
• hawita / Leha Substrate: German-Austrian substrate manufacturer (formerly Hawita) producing peat-based and peat-free growing media; competes with Sonnenerde in the gardening and professional substrate segments across Austria and Germany.

Emerging players

• Carbonfuture: Germany-based carbon removal marketplace and registry issuing biochar carbon removal certificates; comparable to Sonnenerde's CO2 sink certificate revenue stream as a buyer-of-last-resort partner in the voluntary carbon market.
• TerraBona: Danish biochar-based soil amendment producer focused on regenerative agriculture and peat-free substrates; comparable to Sonnenerde as a specialist producer leveraging biochar's soil-carbon benefits for premium positioning.

Regional players

• DCM Austria (De Ceuster Meststoffen): Belgian-origin organic fertilizer and soil amendment company with Austrian distribution; overlaps with Sonnenerde's organic Bodenaktivator, Kompost, and Bio-Schwarzerde categories in the Austrian market.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat6 records

Key risks5 records

Key highlights6 records

Customer concentration

• YouTubeyoutube.com/channel/UCI9wqAKuTelhdToktHJ4s9Q
• LinkedInlinkedin.com/company/sonnenerde
• Instagraminstagram.com/sonnenerde

Compliance9 records

Revenue estimate

Valuation estimate

Number of profiles

Profiles4 records

Subsidiaries1 record

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Sonnenerde