In the history of modern marijuana seeds and strain breeding, one legendary North American company stands above all others—including the legacy Dutch seeds companies. In fact, the most serious and successful professional growers have repeatedly told us to do a major article about Brothers Grimm Seeds, so here it is…
Brothers Grimm is famous for foundational cannabis strains so powerful and well-bred that growers have been using them in their own breeding projects ever since Brothers Grimm started releasing strains in 1996. The company’s most famous strains include Apollo 13, Rosetta Stone, and Cinderella 99.
Brothers Grimm was created by a man who calls himself Mr. Soul. Decades ago, he grew marijuana in his apartment while studying nuclear engineering in college. He contacted one of the earliest Dutch connoisseur seeds organizations, the Super Sativa Seed Club (SSSC), and became their American seed distributor in 1987.
Mr. Soul’s networking with Dutch seed experts gave him access to rare genetics. He also learned professional growing and breeding practices, and used his engineering skills to design grow op hydroponic and climate control systems. He also created a cannabis cultivation workflow protocol that ensures maximal grow op consistency and efficiency.
Innovation has always been a key feature of Mr. Soul’s efforts.
“In 2016 I took an intense interest in feminized seeds and decided to learn everything I could to completely understand them,” Mr. Soul explains. “After many months, I’d compiled sufficient data from scientific journals to allow me to develop a breeding program that produces 100% female seeds reliably if certain concepts were understood and strict procedures were used.”
Mr. Soul also pioneered a method known as “cubing a clone” to create stable, true-breeding strains that exactly replicate the phenotype of unicorn female precursors.
His Cinderella 99 breeding project is an example of how a legendary strain is created. In 1996, Mr. Soul bought Jack Herer buds at a cannabis coffee shop in Amsterdam and discovered seeds in them. He grew out the seeds, got one stellar female he named “Princess.” This Sativa-dominant pheno was compact, making it great for indoor growing, smelled like pineapple, finished after 50 days in bloom phase, had copious resin production, and a very strong Haze high, almost too strong.
Mr. Soul was ecstatic to discover a Sativa-dominant strain that grew small, finished fast, and had zero hermaphroditic traits. In fact, decades later, after many generations of cloning and testing, Princess has never shown hermie traits.
Utilizing pollen from an extremely potent Shiva Skunk male to cross with Princess, he created P.50 Princess (the name indicates the strain is 50% Princess). Mr. Soul used males from the P.50 generation to back-cross with Princess, resulting in a P.75 generation. This back-crossing process continued through another generation to create P.88, and once again to yield P.94, the generation which, when crossed to Princess yields the final generation known as “Cinderella 99,” a cubed version of Princess. Each generation in the cubing process showed successive improvements in stability, quality, and yield.
“Cinderella 99 is every bit as good as a cutting from Princess herself, if not better,” Mr. Soul says. “While Princess and Cinderella share a sweet and fruity taste and an uplifting vibe, Cinderella 99 produces 25% heavier yield and has stronger branch structure. The name Cinderella symbolizes the strain’s journey from humble origins to extraordinary heights, paralleling the beloved fairy tale in which Cinderella transforms from humble beginnings into a Princess.”
Cinderella 99, which quickly acquired nicknames such as C99 and Cindy, became a legend, and Brothers Grimm has gone on to release many more fire strains no other seed company has or can copy. These strains include:
- Rosetta 78 combines Genius and Rosetta Stone, producing a delightful blend of gas, cheese, and sweetness. Growers appreciate its adaptability to training, with flowering times ranging from a swift 60 days to more extended periods for specific phenotypes.
- Ocifer (Cap Junky x Rosetta Stone) is known for vigorous growth, chunky colas, and a distinctive aroma of fine pepper, earth, and lemon. This strain is ideal for cultivators seeking a heavy yielding stable variety. On very rare occasions, extremely unique mutants or phenos appear, many of which are keepers.
- Thai Herer 99 offers a stunning blend of Thai and Jack Herer genetics, producing dense colas and an uplifting, floaty experience. This strain is valued for its spicy, tropical aroma and mellow, stimulating effects.
- Grimm Glue BX is potent, resin-heavy favorite among concentrate makers.
- Rosetta Stoned maintains the exotic aroma of its Rosetta Stone lineage with musk, spice, floral and sweet aromas from heavy-yielding plants.
- Durban Thai x Cinderella 99 (DT x C99) is a Sativa-dominant strain that enhances creativity and concentration. Its intoxicating aromas blend musky incense with hints of black licorice and tart sweetness. Expect baseball-bat colas and a 63-72 day bloom phase.
- Pink Portal OG combines Cap Junky and the ultra-rare Pink OG Kush.
One primary reason we’ve written this article is that Brothers Grimm is one of only 2-3 retail marijuana seeds companies with a professional breeding program that ensures rewarding grower experiences.
The stark truth is that 99% of seed companies don’t use professional breeders or flawless genetics. They have no clue how to create reliable feminized seeds or stable strains without hermies, nor do they care enough to do so.
Mr. Soul is a feminized seed breeding pioneer, he explains that hermie flowers appear because breeders use genetics that produce hermie flowers. They look for females that have hermie flowers, and use the hermie pollen, thus transferring the hermie trait to whatever strains they sell.
That’s why there’s a plague of hermies. It’s not because growers flip plants from 18 hours of light to 12 hours of light “too quickly” or other causes controlled by growers.
In contrast, Mr. Soul makes his own silver thiosulfate, which is used to hormonally induce male flowers on primo female phenotypes selected by Mr. Soul in part because he relentlessly stress-tests them and they never develop hermie flowers. Male pollen from silver thiosulfate-induced perfect female plants applied to other perfect female plants produces seeds that don’t carry hermie traits.
Mr. Soul goes a step further, using third-party labs to test his seeds for germination rate and seed-borne cannabis diseases. In fact, Brothers Grimm is the ONLY marijuana seeds company we’ve found that publicly posts third-party germination rate certificates. And when you look at the Mr. Soul interviews embedded in this article, you see how intelligent, transparent, and articulate he is—rare traits in the marijuana seeds industry.
Another major reason Brothers Grimm is so popular with connoisseur growers is that Mr. Soul’s beautiful life partner Mrs. Soul is CEO of the company and she makes sure growers know they’re valued tremendously.
Founder and former owner of Cannabis Oklahoma Magazine, Mrs. Soul has long been a powerful advocate for marijuana growers and marijuana-related businesses. Her dedication to excellent customer experience is a main reason you see growers praising the company’s ethics, professionalism, customer service policies and procedures.
We’re fortunate that Brothers Grimm still exists: Mr. Soul had retired from the seed business for several years, even though Brothers Grimm was inducted into the High Times Seed Bank Hall of Fame, and thousands of growers wanted more seeds. He moved to Europe in 2002, returned to the USA in 2015, and reopened Brothers Grimm in Colorado due to the state’s favorable cannabis legalization statutes.
As this article is being written in early springtime, 2026, Mr. and Mrs. Soul are building out a new cannabis cultivation facility and enjoying the constantly increasing popularity of their seed lines. The only dark cloud on the horizon is Trump’s federal government may soon implement policies recriminalizing marijuana seeds.
Mr. Soul is worried that interstate seed shipping may become illegal again, after it was legalized when previous legislation specified that cannabis seeds have such little THC that they can’t be considered a controlled substance under federal law. For more information, read here.
Especially if it’s possible that being able to order marijuana seeds and have them shipped to you might become illegal again, the time to order Brothers Grimm seeds is NOW. These genetics are beloved by connoisseur growers worldwide, and are a portal through which you access cannabis history, flawless genetics, and incredible highs.
Growing Marijuana Perfectly! 