Few people have been as visible in the international cannabis industry as Arjan Roskam, the Dutch entrepreneur behind the Green House coffeeshops, Green House Seed Company and the Strain Hunters documentary project. Since the early 1990s, Roskam has occupied an unusual position somewhere between cannabis cultivator, seed-company owner, promoter, genetic collector and media personality. His self-applied title, “King of Cannabis,” became part of Green House branding, but the nickname also reflects how aggressively he pushed cannabis culture into public view. At a time when many breeders preferred anonymity, Roskam invited journalists, celebrities and television cameras into a world that had historically survived by remaining underground. Green House ultimately became one of Amsterdam’s best-known cannabis brands, while its seed catalog spread Dutch genetics throughout Europe and far beyond.
His biography is also inseparable from controversy over how famous cannabis cultivars should be credited. Green House has marketed Roskam as a breeder responsible for numerous award-winning varieties, yet former business partner Scott Blakey, better known as Shantibaba, has publicly stated that much of the foundational breeding behind cultivars such as White Widow and Super Silver Haze was performed by himself and Nevil Schoenmakers while working under the Green House name. The surviving record does not support reducing Green House’s success to one individual. Roskam’s most defensible historical importance is broader: he built the commercial platform, coffeeshops, branding, competitions and media presence through which a remarkable group of breeders and genetics became internationally famous.
Early Travels and an Interest in Cannabis
Roskam has described cannabis as an interest that began well before Green House existed. Green House’s own history places the start of his serious cultivation around 1985, when he was working with exotic seeds obtained from friends and from travel through Thailand, Nepal and other parts of Southeast Asia. In later interviews he has recalled traveling through northern Thailand while still young and encountering traditional cannabis use far removed from the emerging indoor-growing culture of Europe. One account describes Roskam as born in the Netherlands and partly raised in Zambia, giving him early exposure to life outside northern Europe. Whatever details of these stories have become embellished through decades of cannabis mythology, travel clearly became an important theme throughout his later career.
The cannabis market Roskam returned to in the Netherlands was radically different from today’s. Amsterdam coffeeshops were already famous, but imported Moroccan and Afghan hashish remained central to the scene, along with Jamaican, Thai and other imported flower. Locally produced indoor cannabis was only beginning to develop into the highly specialized Dutch industry that would define the following decade. Roskam became particularly interested in Haze and other longer-flowering sativa genetics, even though such plants were less attractive to commercial growers focused on compact growth, high yields and rapid harvests. He has recalled struggling to convince coffeeshops to buy some of these crops. That problem eventually suggested a straightforward solution: if existing shops would not consistently sell the cannabis he wanted to produce, he could create his own venue.
Opening the Green House in Amsterdam
In 1992, Roskam opened the first Green House coffeeshop on Tolstraat in Amsterdam. The location was deliberately designed to differ from the darker, more utilitarian coffeeshops common at the time. Accounts of the business credit Roskam’s wife Rose with helping create a brighter, more polished interior, part of an approach that treated the coffeeshop not merely as a place to purchase cannabis but as a lifestyle destination. That distinction would become increasingly important as Amsterdam tourism expanded during the 1990s. The city had become one of the few places where international visitors could openly compare high-quality cannabis varieties, and Roskam recognized that atmosphere, presentation and reputation could be nearly as important commercially as the product itself.
Competition accelerated Green House’s rise. Roskam entered the High Times Cannabis Cup soon after opening the coffeeshop, and Green House began accumulating awards during the first half of the 1990s. High Times records place Silver Pearl on the podium in 1993 and Citral Skunk in 1994, followed by the famous 1995 victory of White Widow. The Green House name soon became closely associated with the annual competition. Roskam understood the promotional power of these awards exceptionally well. A trophy was not merely recognition from judges; it became a marketing tool that could attract tourists to the coffeeshop and growers to the seed catalog. By the time High Times featured him prominently during the decade, Roskam had become one of the most recognizable personalities in Amsterdam cannabis culture.
Green House Seed Company and the Breeding Team
The history of Green House Seed Company is more complicated than company mythology sometimes suggests. Green House promotional material connects Roskam’s breeding activities to the 1980s, while Shantibaba has stated that he and Roskam formally co-founded the seed company in 1994. What is considerably clearer is that Green House assembled an extraordinary group of cannabis talent during the mid-1990s. Shantibaba brought extensive breeding experience and collected genetics, while Nevil Schoenmakers possessed one of the most important cannabis genetic libraries of the era. Schoenmakers had previously established The Seed Bank of Holland and worked extensively with Haze, Northern Lights, Skunk and Afghan lines before becoming involved with the breeding work surrounding Green House.
That distinction matters because cultivars sold under a company’s name are not necessarily the creation of its owner alone. White Widow illustrates the problem particularly well. The plant won major recognition for Green House in 1995, making both the strain and company internationally famous. Roskam and Green House have long associated the cultivar with their history, while Shantibaba maintains that he created the seed line from Brazilian and South Indian genetics. Similar disagreements surround aspects of other Green House-era strains. Because much of this work occurred in an underground industry without patents, detailed breeding logs or enforceable intellectual-property agreements, absolute authorship is often difficult to establish. The fairest historical interpretation is that Green House provided the commercial banner under which several exceptional breeders, cultivators and genetic collections converged.
Super Silver Haze and the Cannabis Cup Years
If White Widow defined Green House’s mid-1990s reputation, Super Silver Haze helped define its late-1990s dominance. The cultivar combined genetic families related to Haze, Northern Lights and Skunk, three foundations of the Dutch breeding revolution. Super Silver Haze became a landmark competition variety, winning major Cannabis Cup recognition across successive years in the late 1990s. High Times records associate Green House with its victories and continued success, while Shantibaba has specifically credited breeding work on the line to himself and Nevil Schoenmakers. Roskam’s role was particularly powerful on the commercial side: Green House presented these genetics to an international audience, sold the finished product through Amsterdam and converted Cannabis Cup prestige into worldwide seed demand.
The departure of Shantibaba toward the end of the decade changed Green House significantly. Shantibaba says he sold his share of the business to Roskam in 1998 before pursuing medical cannabis work in Switzerland and establishing Mr. Nice Seedbank with Howard Marks and Schoenmakers. Roskam continued Green House without him, gradually building a new breeding and cultivation team. Rather than ending the company’s competitive run, the transition produced another generation of prominent varieties. Hawaiian Snow won major Cannabis Cup recognition in 2003, Arjan’s Ultra Haze became a leading competition cultivar during the middle of the decade, and Super Lemon Haze won back-to-back High Times Cannabis Cups in 2008 and 2009. Those later successes demonstrated that Green House had become an institution capable of outlasting its original partnership.
Franco Loja and a New Era for Green House
One of Roskam’s most important later partnerships was with Italian breeder and cultivator Franco Loja. Loja became Roskam’s close collaborator, partner and eventually one of the most recognizable public faces of Green House. High Times described him after his death as Roskam’s right-hand man for almost two decades. Their personalities complemented one another: Roskam was the assertive businessman and promoter, while Loja became respected for his cultivation knowledge, enthusiasm and willingness to spend months working in difficult conditions. Together they represented Green House during a period when the internet and online video were changing how cannabis information traveled.
Their collaboration also helped shift Green House away from simply selling finished strains and toward telling stories about where cannabis genetics originated. This development became the foundation of Strain Hunters. Instead of presenting a new hybrid only through photographs and catalog descriptions, Roskam and Loja traveled to areas associated with traditional cannabis cultivation, filmed local farmers and searched for populations that had developed with limited influence from modern commercial hybrids. The concept merged plant collecting, adventure documentary and brand promotion into something the cannabis industry had rarely attempted at such scale.
Strain Hunters and the Search for Landrace Cannabis
The Strain Hunters project took Roskam and his team into regions of Africa, Asia, the Caribbean and South America in search of traditional cannabis populations. Expeditions documented by the organization have included Malawi, India, Morocco, Trinidad and St. Vincent, Jamaica, Eswatini, Colombia, the Democratic Republic of the Congo and South Africa. The official mission describes the effort as locating and preserving vulnerable landrace cannabis genetics before they disappear through hybridization and changes in agriculture. Whatever one thinks of the commercial branding surrounding the expeditions, the documentaries drew enormous attention to an important botanical problem: traditional cannabis populations can be diluted when imported modern hybrids are repeatedly introduced into isolated farming regions.
The project reached a broader audience when VICE accompanied Roskam and the Strain Hunters to Colombia in 2013 for Kings of Cannabis. Cameras followed the group through Colombian cultivation regions as they searched for old genetic populations. The production exposed viewers who knew little about seed breeding to the idea of landraces, genetic selection and cannabis agriculture outside North America and Europe. It also strengthened Roskam’s carefully constructed public identity as a globe-traveling genetic hunter. The documentaries were undeniably promotional, yet their influence should not be dismissed simply because a commercial seed company financed them. For a generation of growers, Strain Hunters was among the first widely viewed media projects to connect modern cannabis hybrids with the farmers and regions from which older breeding material originated.
The Death of Franco Loja
The Strain Hunters story took a tragic turn in January 2017, when Franco Loja died after contracting malaria while working in the Democratic Republic of the Congo. He was only 42. High Times reported that Loja had been in the region researching cannabis and exploring the potential use of CBD in relation to malaria when he became ill. His death shocked the international cannabis community and left Roskam without the collaborator who had become nearly inseparable from Green House’s public image.
Roskam continued Strain Hunters after Loja’s death while repeatedly emphasizing his former partner’s passion and contribution. Later expeditions returned to Africa, and Green House continued using large-scale field selection as part of its breeding narrative. In a 2022 interview, Roskam described operations capable of planting tens of thousands of seeds while searching for unusual individuals, including work in several locations outside the Netherlands. Whether every claim made about the scale of those programs can be independently verified, they reveal the breeding philosophy Green House increasingly promotes: genetic diversity becomes more useful when breeders can evaluate very large populations rather than making selections from only a handful of plants.
Building the Green House Cannabis Empire
Roskam’s greatest talent may ultimately be entrepreneurship rather than plant breeding alone. Green House expanded from a single coffeeshop into a network encompassing coffeeshops, seeds, plant nutrients, documentaries, merchandise and other cannabis ventures. Roskam embraced branding years before much of the cannabis industry learned to operate like conventional consumer businesses. Celebrity visits became part of Green House mythology, competition trophies were displayed as proof of quality, and the company treated packaging and media appearances as important components of selling genetics. High Times later included Roskam among its influential cannabis figures, acknowledging the scale of his impact on both cultivation culture and international cannabis marketing.
He has also continued adapting Green House genetics to a rapidly changing market. During the 2010s and 2020s, American breeding increasingly became centered around dessert varieties, Cookies-derived genetics and elite clone-only cultivars. Roskam responded by collaborating with newer breeders rather than treating them solely as competitors. Green House has worked with companies such as Compound Genetics, combining modern American material with older Green House lines. Roskam has argued that keeping older genetics available is essential because repeatedly recycling the same fashionable families risks narrowing the breeding pool. That philosophy connects his present business to the Haze obsession of his early years: commercially inconvenient genetics may contain qualities worth preserving precisely because they fall outside contemporary fashion.
A Complicated but Lasting Cannabis Legacy
Any serious biography of Arjan Roskam has to separate branding from breeding history. The Green House story is filled with overlapping claims, fractured partnerships and cultivar histories written years after the plants themselves became famous. Roskam unquestionably benefited from the work of exceptionally talented breeders, particularly Shantibaba and Nevil Schoenmakers, and it would be historically inaccurate to assign him sole authorship for all of Green House’s classic 1990s genetics. At the same time, reducing him to a marketer ignores another reality: revolutionary genetics have limited cultural influence if nobody successfully distributes, presents or promotes them. Roskam built one of the platforms through which Dutch cannabis breeding became a global phenomenon.
More than three decades after the first Green House coffeeshop opened, Roskam remains involved in the company and its international breeding projects. His career has moved through nearly every stage of modern cannabis culture: underground cultivation, Amsterdam coffeeshops, Cannabis Cup competition, international seed distribution, landrace expeditions, internet documentaries and the emerging legal global market. Whether remembered as the “King of Cannabis,” an ambitious entrepreneur, a controversial self-promoter or some combination of all three, Arjan Roskam helped change the way cannabis genetics are marketed, experienced and discussed around the world. His most enduring legacy may therefore be larger than any single strain. He helped turn cannabis breeding from an obscure underground craft into an international culture with recognizable breeders, brands, competitions, genetic histories and audiences spanning continents.
