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  • Cannabis

Is the UK medical cannabis industry too reliant on American genetics?

Cali strains are dominating the cannabis world right now, from your local shottas menu to the formularies of clinics. Is the UK medical cannabis industry meeting the needs of patients with these strains, or are they putting profit above all else?
  • Neil Cartwright
  • February 27, 2025
  • 5 minute read

In the brightly lit halls of corporate cannabis events, there is a well-worn phrase being peddled by every producer: “From seed to sale.”

This mantra has come to define the industry. Companies are rightly proud of their ability to select the right seeds, grow them optimally, and convince you, the consumer, to buy the end product.

The seed is at the start and heart of the cultivation process. But behind every seed lies a hidden story of dedication, countless growing cycles, and the painstaking art of selective breeding. This process wields a powerful influence on the cannabis being prescribed to UK patients, and it’s not necessarily a positive one.

A 2023 Allied Market Research report valued the global cannabis seeds market at $1.3 billion in 2021, projected to reach $6.5 billion by 2031, with growth expected in feminised and auto-flowering seeds alongside regular seeds.

Creating new cannabis strains is a lengthy process that involves both art and science. Each grow cycle takes 12-16 weeks, so there is an upper limit to how many can be produced each year. Hunting for the “keepers,” rare plants with unique genetic traits worth breeding into the next generation, demands an expert eye.

“Picking out the plants takes practice and time,” say Conscious Genetics, a breeder with over 10 years of experience. “First I decide the features I’m looking for, say, flavour, yield, grow times or whatever. Then I select the ‘best’ plants with those traits and subsequently cross-breed those to keep building the characteristic I’m looking for. But then, you’ve obviously got to grow crops using those seeds and cross-reference the flavour. So, it’s a constant cycle of trial and error, trying to stay on top of which characteristics you’re selecting from the strongest looking plants.”

Dara, a veteran breeder at Barney’s Farm with 28 years of experience, offers a stark assessment of the breeding process. “It’s all down to luck, one in a million”, he explains. “You might think if you cross Zkittlez with something generic like White Widow, you’d get a bigger yield, but it won’t adopt the flavour of the Zkittlez. So, you just have to keep going and hope one of the plants mutate and you get something unique.”

Breeders seek genetic diversity through global Pheno Hunting expeditions. They collect seeds from Landrace strains, varieties of cannabis that have grown in the wild, letting nature define their genetic traits. From the highlands of Southeast Asia to the plains of Africa and the valleys of South America, the goal is to find “The Unicorn,” as described by Landrace Genetics: plants with undiscovered genetic properties that can be cross-bred to create strains with unique flavours, higher yields, more THC or CBD, faster grow times, or combinations of all the above.

Seed breeders are integral to the medical cannabis production process because they have a deep understanding of cannabis genetics, from yield potential to terpene profiles. Their expertise goes beyond simple cultivation; a good breeder will detail the flavours and aromas of specific strains, their history, lineage, unique characteristics and ideal growing conditions.

Here, things begin to get complicated for patients in the UK. Cali strains, which command high prices on the recreational market, also dominate the medical market. While patients may be attracted to clinics as a legitimate source for these strains, they’re unlikely to be aware these are grown for their commercial properties, not necessarily the right ones for medical.

The Yanks are coming

In the last decade, two forces have shaped the American cannabis landscape: a booming recreational market and the rise of celebrity breeders.

23 US states now offer legal dispensaries, with California leading the charge.

The profit potential in the fiercely capitalist recreational market has sparked the celebrity breeder phenomenon. Larger-than-life personalities have emerged, building their brands through social media and creating a new kind of cannabis stardom. Influential figures like Berner from Cookies, the Sherbinski brothers (Gelato), Seed Junky (Permanent Marker, LA Kush Cake), Compound Genetics (Jet Fuel), DNA Genetics and Jungle Boys have become tastemakers, with their latest strains instantly creating hype and importantly, demand.

The competitive American market has led to another crucial difference. In a recreational market, substantial commercial pressures favour strains with high yields, quick growth, and smaller footprint. This allows farmers to maximise profit through more grow cycles each year.

Driven by commercial pressures, American breeders have gravitated towards Broad Leaf Cannabis varieties, discovered in the Kush Mountains during the 1980s. These naturally compact plants, evolved to cope with harsh Himalayan winters, suit modern commercial growing. Their 12-week growth cycle shaped by the shorter summers in their natural habitat.

Commercial strains from broad leaf cannabis are Indica dominant and high in terpenes such as Myrcene and Beta Caryophyllene. This explains the shift towards sleepy couch lock varieties.

The cali weed effect is evident in the UK’s medical cannabis formulary. MedBud.wiki‘s latest listings resemble an American dispensary menu: White Runtz, Sunset Sherbert, GMO, Bubba Kush, Tiger Milk, Gary Payton. These aren’t just names, they’re brands. Each a testament to California’s overwhelming influence on UK cannabis.

The Americanisation of the UK medical market means patients are mostly being offered strains developed for California’s competitive recreational market, where brand recognition and commercial success often trump therapeutic value.

Does this matter?

The medical benefits of cannabis largely depend on the genetics, whether they trace back to sativa or indica strains, and which other compounds are present in the plant besides THC and CBD.

Cali strains are usually indica-dominant and favour fruity or spicy terpenes. Sativa-dominant strains have higher levels of limonene and less myrcene, which is why they’re often described as “head highs.” 

Try to find a pure sativa strain on the formularies of UK clinics and pharmacies and you’ll struggle. The available Sativa strains are variations of Blue Dream, Silver Lemon Haze and Green Crack, all developed in the US for commercial markets. When our medical market is dominated by strains designed for recreational use in California, are we meeting the needs of British patients?

Where are all the sativa strains?

Sativa strains are popular in Europe, where ‘grow your own’ markets have emerged. Why aren’t we seeing sativa-dominant strains in the UK medical market, considering their popularity with our next-door neighbours?

Growing these strains costs more. Like all businesses, UK medical cannabis producers benefit from economies of scale. If they buy from a Canadian commercial grower, they can secure a lower price by piggybacking off a strain intended for commercial release. This explains why the UK medical market is so US/Canada heavy, since our clinics rarely get offered a ‘non-commercial’ strain from the large-scale producers supplying the vast majority of our product.

UK clinics claim to prioritise patient interests, but if this were true, they would source strains with different cannabinoid and terpene profiles to offer doctors more variety when prescribing.

Time to move beyond Cali

For generations, European, African and Southeast Asian breeders have perfected cannabis genetics, combining traditional knowledge with modern techniques to develop strains that often outperform American counterparts in diversity and therapeutic potential.

Yet the UK medical cannabis industry remains fixated on California’s commercial brands. This isn’t just about missing out on genetic variety, it’s about failing to recognise that not every patient’s needs can be met by strains designed for the American recreational market.

As Britain’s medical cannabis market matures, it’s time to look beyond the hype of Cali weed and focus on the patient. Healing shouldn’t be determined by geography or marketing success.  

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Neil Cartwright

Neil is the co-founder of Plantz, a community driven platform for people who are passionate about the science behind natural medicines and the power of plants to heal.

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