Upon exhaling a deep drag from a joint of Blueberry Cookies grown by City Farmers BCN the smoke from my hit travels upward into the rafters of a 16th century modernist palace in the heart of Barcelona’s Gothic Quarter. As the smoke rises, I contemplate the significance of the moment and celebrate the freedom of enjoying weed in a country where cannabis still exists within a gray area, decriminalized for personal use and cultivation, but illegal for commercial sales. I’m in Barcelona, Spain for an international gathering focused on cannabis genetics. More specifically, I’m within the Hash Marihuana & Hemp Museum at a party celebrating the collaborative efforts that bridged a domestic-international divide to unite two storied cannabis seed companies, Sensi Seeds and Humboldt Seed Company. Within their collaboration lies the dawning of a new chapter in the history of marijuana, one which continues the tradition of legendary fusions of Californian and European genetics that started in the 1970s when the hybridization of cannabis began.
The collaborative project is called Breeding Grounds and resulted in the release of four new feminized seeds: The Bird (OG Kush x Humboldt Dream x Larry Bird), Auto Pineapple Kush Cake (Pineapple Muffin autoflower x Banana Kush Cake autoflower), Auto Amnesia Jelly (Mint Jelly autoflower x Amnesia autoflower XXL), and one that lies within the highly popular and heavily lauded Z terp family, Purple Berry Muffinz (Purple Bud x Blueberry Muffin x Zkittlez). But arguably more significant than the lineage of the new cannabis cultivars is the symbolism of what they represent. Sensi Seeds, which inherited the genetics of the world’s first cannabis seed bank—Nevil Schoenmakers’s The Seed Bank of Holland—brought the world classic cultivars such as the sativa-dominant Jack Herer and has been in the business of selling cannabis seeds from its home base in Holland since the 1980s. Humboldt Seed Company, founded in California’s Emerald Triangle in 2001, has built a reputation as a trusted breeder via enormous phenohunts and award-winning cannabis such as its signature strain Blueberry Muffin. The fusion of the two companies in 2023 harkens back to the beginnings of cannabis breeding in the 1970s, when people like Sam the Skunkman and Ed Rosenthal became the catalysts for fusing European and Californian cannabis genetics, an action that created the world’s first cannabis hybrids.
“The first time I heard about The Seed Bank, which is the precursor to what is now Sensi Seeds… my uncle had a shed where he would keep all the gardening stuff and in that shed he would stash Cannabinoids Garden magazines and I remember sneaking into his shed—because we would sometimes you know, borrow some weed from our uncle—and we’re looking at his Cannabinoids Garden and in the back of Cannabinoids Garden we saw an advertisement for The Seed Bank,” explains Benjamin Lind, co-founder and chief scientific officer of Humboldt Seed Company. “And it just kind of clicked like, ‘Whoa, you can actually order seeds.’”
From a young age, Lind was observing his family members making their own cannabis crosses and learning about the importance of seeds to ensure the next year’s harvest. Sensi Seeds, he says over an early morning eating lychee fruit acquired from one of Barcelona’s famed food markets, was the first cannabis seed company that ever came into his vision. And, once he met the people behind the company and toured their facility decades later, he learned that the breeding work they had been doing aligned with his own.
“A lot of our processes are very similar,” he says. “All breeders come at breeding cannabis differently and very few have similar beliefs or similar philosophies, but we mesh really well.”
This meshing of two similar minds in the cannabis breeding world was more than a coincidence, it’s the result of years of effort put in by none other than cannabis cultivation expert Ed Rosenthal, who tells me he’s done writing books and is now more interested in acquisitions and mergers. Rosenthal’s relationship with Sensi Seeds goes back years. A mutual friend who had a cannabis club and magazine introduced Rosenthal to Ben Dronkers, the founder of Sensi Seeds, back in the 1980s. Once introduced, the two began to collaborate with each other on a museum in Amsterdam dedicated to the history of the cannabis plant which first opened in 1987.
“At the same time Nevil [Schoenmakers] was indicted so he sold his business, The Seed Bank, to [Sensi Seeds] and he took off for the wilds of Australia and he was never brought to the U.S.,” Rosenthal explains. “We stayed close and then [Dronkers] hired me off and on at different times to do things and then also put in, I think, $50,000 to $100,000 into my defense.”
The defense Rosenthal is referring to was a federal trial that began in the early 2000s when he was found guilty of three felonies related to the cultivation and sale of marijuana. After the trial, the jurors—who had not been provided with the crucial information that Rosenthal had been deputized by the city of Oakland, California to grow medical marijuana—denounced their verdict and in 2003 Rosenthal was ultimately sentenced to a single day in prison, time served.
Rosenthal calls Sensi Seeds, which is now run by Dronkers’s son Ravi Dronkers, a “legacy family,” and says when he saw them interacting with Humboldt Seed Company he realized the “cultures weren’t that different.”
“I knew this was the one to go and I just did everything so that it didn’t get fucked up,” he says. “I’m really excited about this. This is going to be very big.”
The announcement for the collaboration came in mid-March at the Hash Marihuana & Hemp Museum’s second iteration in Barcelona and included flutes of cava alongside a bowl filled with the Spanish-grown Blueberry Cookies so guests could roll their own joints. Guests in attendance included Jack Herer’s son, Dan Herer, who was spotted taking a photograph of a framed picture of his father on display within one of the rooms devoted to hemp. In a country that resides within the legal gray market for cannabis, smoking and enjoying flowers and concentrates takes place within private social clubs and spaces that are cannabis-friendly. This clearly includes the cannabis-themed museum during a private event, but also includes restaurants which will pull down their rollup doors to offer discretion for diners to smoke weed at the table while the waitstaff also lights up.
Over a candid evening conversation after one of those smoky Barcelona dinners, Rosenthal gets in a discussion with Nathaniel Pennington, co-founder and CEO of Humboldt Seed Company, about cannabis breeding. The basics of cannabis breeding involve creating new expressions of the botanical by crossing, or pollinating, the female flower with pollen from a male plant. An F1, or first generation, occurs when breeders cross two landraces—cultivars that are native to specific regions and have not been bred—or when breeders cross two inbred lines. The final hybridized result that’s released by reputable seed companies comes after at least four generations of inbreeding. The reason that the lines are inbred, or bred from plants that share similar genetics, is to stabilize the seeds ensuring that, once the seeds are grown into plants, they retain similar physical characteristics. Cannabis plants have a complex set of DNA and, like two sisters from the same family, when two cultivars are brought together the results will not be genetically identical, but rather, similar but different expressions known as phenotypes. The art of creating cannabis seeds involves the painstaking work of getting to a point where the expression of all the seeds will be the same, a process that is known as stabilizing the genetics.
“With breeding it’s not true science until it’s repeatable,” Pennington explains. “[True breeding doesn’t occur] until you can perform the same experiment, which I would say is the same seed population times the same seed population and find the same phenotypic outcome. And if you can’t reproduce that experiment then you haven’t really accomplished anything except for you’ve made a clone line which can be forever propagated as a clone, but that’s a bit of a handicap if you ask me.”
In a world filled with companies making dubious claims about the stability of their seed lines some companies, like Sensi Seeds and Humboldt Seed Company, stick to the science. In doing so, these seed banks bless humanity with reliable cultivars that cross oceans and territorial boundaries to contribute to the diverse genetic expression of the world’s most favored flower.
“Both of our families have worked for generations to preserve the very best lines and bring them to the modern market,” Lind said through a press release about the Breeding Grounds project. “We both evolved on different continents, with different selective pressures. Even though we live a world apart we have a very similar philosophy based on love and respect for the plant. It was natural we would cross-pollinate the best from Amsterdam with the best of Northern California.”