Green House Seed Company
Dutch seedbank tied to Amsterdam coffeeshops and Strain Hunters landrace-collection expeditions.
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Green House built real fame through Cannabis Cup wins in the 1990s–2000s, but there's no objective way to rank seedbanks by awards. The bigger issue: authorship of foundational strains like White Widow is genuinely disputed—Shantibaba and others claim credit Green House disputes. Current seed stock consistency, strain stability, and phenotype reliability are reported as hit-or-miss by growers, with no published quality-control data. 'Most awarded' is marketing, not fact.
What it is
Green House Seed Company is a Netherlands-based cannabis seed producer that sells feminized, regular, and autoflowering seeds through its official website and authorized resellers [1]. The company shares branding and personnel with the Green House coffeeshop chain in Amsterdam and with Arjan Roskam's 'Strain Hunters' media project, which documents expeditions to collect landrace cannabis genetics from various countries.
The company markets itself as 'the most awarded' seedbank in the world, citing High Times Cannabis Cup placements from the 1990s and 2000s Disputed. This claim lacks an independent registry against which to verify it—other Dutch seedbanks including Sensi Seeds and Dutch Passion make overlapping historical claims to cannabis industry prominence [2]. The 'most awarded' tagline is marketing language, not an audited statistic.
History and ownership
Arjan Roskam opened the first Green House coffeeshop in Amsterdam in 1985. The seed company developed from the coffeeshop's in-house breeding program during the 1990s, often in collaboration with breeder Franco Loja. Loja became the public-facing representative of the Strain Hunters expeditions before his death in 2017 from cerebral malaria contracted during a collection trip to Colombia [3].
The company remains privately held and does not publish audited financial statements or detailed corporate records No data. Public information about current ownership structure, breeding staff, and seed production facilities is limited to company publications and press interviews. Independent verification of operational details beyond Roskam's public profile is not available.
Catalogue and genetics focus
Green House's seed catalogue centers on hybrid strains associated with the company's name or breeding work, including White Widow, Super Silver Haze, Hawaiian Snow, Arjan's Haze #1/#2/#3, Great White Shark, and Neville's Haze [1]. Several of these strains are foundational to modern hybrid cannabis genetics and are sold by multiple breeders worldwide.
The exact parentage and first breeder of key strains like White Widow and Super Silver Haze is contested between Green House, Shantibaba (Mr. Nice Seeds), and other Dutch breeders active in the 1990s Disputed. There is no neutral third-party arbiter for historical breeder credit in cannabis, and both sides of these disputes have documented supporters and claims.
The Strain Hunters project sourced landrace material from Malawi, India, Colombia, Morocco, and other regions. How faithfully modern commercial seed releases reproduce the original plants or prize-winning phenotypes is a common complaint in grower forums and online reviews Anecdote. No published quality-control data or batch consistency testing exists in the public domain.
Reputation and awards
Green House accumulated a substantial number of High Times Cannabis Cup placements between approximately 1994 and 2010, including documented wins for White Widow, Super Silver Haze, Hawaiian Snow, Arjan's Haze, and other strains [2]. High Times published these results contemporaneously, making the historical record verifiable through the magazine's archives [2].
Important caveats:
- The Cannabis Cup has faced documented criticism regarding judging methodology, commercial restructuring, and pay-to-enter competition categories.
- A cup win in a specific year with a specific plant does not guarantee that current seed stock of the same strain name will produce identical results.
- 'Most awarded' is marketing shorthand and has not been independently audited against other seedbanks' historical records.
Grower reports on independent seed forums and review platforms are mixed Anecdote. Some report stable genetics and strong results; others report inconsistent phenotypes, hermaphroditism in feminized lines, and deviation from historical trait descriptions. These are anecdotal accounts, not controlled data, and no peer-reviewed study of Green House seed batch consistency has been published.
Controversies and disputed strain lineage
The most persistent controversy concerns disputed authorship of major strains. Shantibaba (Scott Blakey), a cannabis breeder who collaborated with Green House in the mid-1990s before co-founding Mr. Nice Seeds with Neville Schoenmakers and Howard Marks, has publicly claimed he bred White Widow and other lines that Green House credits to itself Disputed. Green House disputes these accounts. There is no neutral arbitration system for breeder credit in the cannabis industry, and historical documentation is fragmented across personal archives, interviews, and trade publications.
Arjan Roskam is a polarizing figure in the Dutch cannabis scene—praised by supporters for building an internationally recognized brand and genetics library, and criticized by detractors for aggressive self-promotion and contestable claims [3]. Franco Loja's 2017 death from malaria on a Strain Hunters expedition received significant media coverage and raised questions about the safety of fieldwork on strain-collection missions [3].
No major regulatory action against the seed company has been publicly reported, though Dutch coffeeshop operators generally have operated within the Netherlands' gedoogbeleid ('tolerance policy') framework [4].
Availability and legal considerations
In the Netherlands, cannabis seeds are sold as novelty or collector items under the country's tolerance policy; actual germination and cultivation are separately regulated [4]. Green House distributes seeds internationally through its official website and authorized resellers.
The legal status of importing, possessing, and germinating cannabis seeds varies widely by jurisdiction and changes frequently. In some countries, seeds are legal to possess but not to germinate; in others, they are fully prohibited; in some U.S. states and Canadian provinces, they are sold through licensed retail. Buyers are responsible for verifying local law before any transaction No data.
Weedpedia does not endorse purchase from any seedbank and does not provide germination guidance, stealth shipping advice, or customs information.
What to verify before ordering
If you are considering Green House as a seed source, useful verification steps include:
- Current activity. Check that the company's website is actively maintained and that customer support responds to inquiries. Seedbank operational status can change; this profile was last verified in October 2026.
- Local legality. Independently verify seed import, possession, and germination law in your jurisdiction before any transaction.
- Strain history. If a specific strain's origins matter to you—for example, White Widow or Super Silver Haze—research multiple breeder accounts and historical sources rather than relying on one company's marketing or website claims.
- Independent grower data. Cross-reference recent grower reports across multiple independent seed forums and review platforms. Weight documented, repeatable observations over single anecdotes.
- Seed viability and quality. Weedpedia cannot confirm seed germination rates, shipping success, or phenotype stability for Green House or any other seedbank. Published third-party testing of seed viability is rare in the cannabis industry.
Sources
- Practitioner Green House Seed Company. Official seed catalogue and company website.
- Reported High Times. Cannabis Cup historical results archive, 1988–2010s.
- Reported High Times. 'Franco Loja, the Strain Hunter, Dies at 42.' January 2017.
- Government Government of the Netherlands. 'Toleration policy regarding soft drugs and coffee shops.' Dutch government policy overview.
How this page was made
Generation history
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