Green House Seed Company
An Amsterdam seed breeder with a famous name, a crowded origin story and a few disputes over who did what.
- 42cup results
- 9first places
- 1999–2024active in results
- 7cups entered
01Beginnings
Green House Seed Company began in Amsterdam in 1994. Wikipedia's article on Arjan Roskam says he co-founded it with Scott Blakey1. The same article says the company was based on a seed collection that Sam Skunkman brought to the Netherlands in 1984, which included classic lines such as Skunk #1, Original Haze and Hindu Kush1. Roskam is also described as the founder of the Green House coffeeshops, a separate venture from the seed company1. This page covers the seed company only.
Leaf Nation tells a three-person version. In its account, Nevil Schoenmakers and fellow Australian breeder Scott Blakey, also known as Shantibaba, co-founded the company with coffeeshop owner Roskam2. Schoenmakers had earlier sold his Holland Seed Bank and Cannabis Castle to Ben Dronkers, but he kept breeding, at first for the company he used to own2. Wikipedia names only Blakey and Roskam, so the sources differ on who was involved12. A 2024 listicle says Roskam began selling seeds in Amsterdam in the 1980s3. That conflicts with the 1994 date and is not corroborated here.
02The story so far
The partnership did not last. Wikipedia says Blakey sold his share to Roskam in 1998, leaving Roskam as sole owner1. Leaf Nation places the break-up near the end of the 1990s and attributes it to a change in Dutch law on seed production, along with clashing interests and egos2. In that telling, Schoenmakers and Shantibaba cut ties with Roskam and later teamed up with Howard Marks on Mr. Nice Seed Bank2. The two accounts overlap on the split but not on every detail.
Wikipedia credits the company with Cannabis Cup wins for Arjan's Haze #1 in 2006 and Super Lemon Haze in 2008 and 20091. Leaf Nation says the 1990s team developed several Cup-winning strains, including White Widow, Super Silver Haze, White Rhino and Nevil's Haze2.
Credit has been a recurring argument. Wikipedia says Roskam's claims about helping create White Widow and Super Silver Haze contradict Blakey's account, and that Blakey is widely believed to be the originator1. Leaf Nation lists those strains among the team's successes without naming individual breeders2. Wikipedia also notes scrutiny of Roskam's attempts to register trademark patents for popular seed varieties1. It further reports that he has been accused of paying off judges at past Cannabis Cups; no detail or outcome is given, and it remains an accusation1.
03Culture and character
Roskam markets himself with some theatre. He is known as the "King of Cannabis", a title Wikipedia labels self-appointed, and others call him the P.T. Barnum of cannabis1. In 2008 he started Strain Hunters, a documentary series that follows searches for rare or vulnerable landrace varieties around the world1. He also appeared in the "Marijuana" episode of the show Drugs, Inc., where he talked about his work1.
A 2024 listicle says Franco Loja started out as a breeder at Green House Seeds and went on to become a global cannabis ambassador3. Beyond these points, the sources collected here say little about the company's day-to-day working culture.
04Where things stand now
Wikipedia's undated text describes Roskam as sole owner of the seed company1. None of the sources gathered here makes an ownership statement dated later than 1998, so the current position is not documented beyond that description.
A post dated 27 December 2024 still presents Green House Seeds as a leading name. It claims, without a source, that the company has won more Cannabis Cups than any other, which should be read as promotional3. The same post credits Roskam with White Widow and Super Lemon Haze, which echoes the credit dispute described above rather than settling it3.
05What comes next
No announced plans or outlook for Green House Seed Company were found in the sources gathered for this page. What happens next is not documented.
On the podium, in our data
CannaLib records 42 cup results naming Green House, between 1999 and 2024, 9 of them first places.
Where they showed up
- IC420 Growers Cup (ICMag 420 Cup) · 12 entries
- High Times Cannabis Cup (Amsterdam) · 11 entries
- Expogrow Cannabis Cup (Irún) · 8 entries
- Spannabis Champions Cup · 6 entries
- Highlife Cup (Netherlands) · 3 entries
- Autoflower World Cup · 1 entries
Strains behind the results
Sources
- Arjan Roskam (Wikipedia)
- Cannthropology: The Original King of Cannabis - Leaf Nation
- Top 10 Cannabis Industry Success Stories (27 December 2024)
Written from the sources above and checked on 2026-10-29. Spot an error? Tell us on the contact page.