This Could Be The Strongest Autoflower Seed On The Market (With Over 25% THC)

Following on from yesterday’s article about the best auto seeds to grow outdoors in the UK, this article will look at one of the strongest autos on the market: Auto Cinderella Jack from Dutch Passion. 

This recently developed strain – a cross of Cinderella 99, Jack Herer and Magnum Auto from Buddha Seeds – has been independently verified by two separate laboratories, which have shown THC levels of almost 26%.

Auto Cinderella Jack seeds have always been capable of THC levels above 20%, but it was a surprise when a couple of test results revealed levels of almost 26%. 

According to famous seed bank Dutch passion, this is the highest THC level they have ever seen in an autoflowering cannabis variety (the first over 25% THC) – and they’ve spent many years breeding and researching autos.

The first test showed 25.94% THC, while a confirmation test by a separate lab showed 24.28% THC. Smaller amounts of CBD, CBN, CBG, THCV, CBC and CBDV were also present.

The Auto Cinderella Jack plants were grown organically under LED lights in 7 litre containers – conditions similar to those used by many home growers – proving that these levels can be obtained by home growers fairly easily.

Passion for cannabis

Dutch Passion regularly tests both existing strains and research projects, emphasising that “laboratory testing is mandatory on any new research variety. Without lab tests to show terpene profiles and cannabinoid content it isn’t really possible to identify and professionally breed the best parent varieties to create new strains.

“Seeds of existing Dutch Passion strains are regularly taken, grown and tested for various reasons, from ensuring quality standards are being maintained, to entering samples for cannabis cups.”

Boosting THC

It’s widely thought that most home growers will achieve around 15% THC in their crops. 15% THC is plenty and will produce a strong high when consumed. 

Getting up to 20% THC and beyond tends to be achieved by more experienced growers who can maintain an ideal environment during the growing process.

THC levels of 25% and above are rare, despite what you may see claimed online. To achieve 25% THC you need the very best cannabis seed genetics, as well as the experience to deliver optimised conditions to the plants from start to finish. Supplemental UV light during the flowering stage also helps. 

How to grow Auto Cinderella Jack 

To help you grow this powerhouse of a strain, Dutch Passion have laid out how they did it. 

The plants were grown using LED grow lights from California Lightworks (the Solar System 550, using 400W). LEDs are preferred by many of the top growers because the light spectrum is optimised for cannabis cultivation and has a low heat signature. 

A cycle of 20 hours of light to 4 hours of darkness was used. 

They were grown in 7 litre containers, with a grow medium of 4:1 mix of coco:light-mix soil. The plants were grown organically, using the full Biotabs nutrient line. 

Dutch passion states, “the plants were then simply given water for much of their life. The slow release BioTabs nutrients gradually releases essential minerals and nutrients, making it very easy to grow cannabis. Towards the end of the grow, an occasional top feed was given.”

A technique called ‘Blue Light Treatment’ was also used. This is where the plant receives only blue light wavelengths for the last 2-3 days. This is thought to increase terpene and cannabinoid production prior to harvest.

Too good to be true?

While Dutch Passion invests in accurate testing from independent laboratories, not all seed companies take the same measures. It’s not uncommon for companies to use less-than-reliable testing methods and cherry pick the results.

Therefore, be sceptical when companies claim exceedingly high THC levels based on inaccurate testing. The last thing you want is to do is waste several months growing low quality seeds. Choose a seed company you can trust.

Terps for day

As well as a powerful cannabinoid profile, Auto Cinderella Jack also impresses with a strong taste which connoisseurs will adore.

Alpha Pinene, with the scent of fresh forest pine, is the dominant terpene in Auto Cinderella Jack, accounting for around 40-45% of the total terpene content.

Beta Myrcene is the next most dominant, accounting for 20-25% of the terpene. Myrcene is also found in hops, thyme and other herbs with a pleasant floral scent.

Beta Caryophyllene accounts for 15-20% of the terpenes, it’s an essential oil found in cloves. The citrus scent Limonene is also found in Auto Cinderella Jack.

This combination of terpenes gives a strong, piney-spicy aroma and taste.


If you haven’t grown autoflower seeds before, you’re in for a treat. Not only are they quick and easy to grow, they can be pretty potent too. And Auto Cinderella Jack from Dutch Passion is probably one of the strongest around. 

With a potential to produce over 25% THC, a strong terpene profile and a wide range of minor cannabinoids, Auto Cinderella Jack seeds show just how good autoflower genetics have become in recent years.

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