Black Jack

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We will always strive to dispatch orders for special delivery placed before 10am on the same working day, however please note all orders are subject to our usual processing time of upto two working days. Quoted delivery time is from point of dispatch.

 Free Cannabis Seeds

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When you shop at the London Seed Centre you are guaranteed a minimum of one free seed with every order.

The more you spend the more free seeds you’ll receive bundled in with your order.

What’s more, our freebies are some of the most popular strains on the market provided by the most reputable manufacturers, so rest assured you won’t be disappointed!

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*Kindly note that free seeds strains are subject to availability, and may be swapped out with different strains if they become out of stock. We alway do our best however to supply a strain of similar characteristics to the seeds on your order. Thank you for understanding.

Black Jack is a feminised strain that displays true hybrid vigour, delicious earthy pungent flavours and produces an exhilarating high. A fine blend of indica and sativa genetic that takes less 8- 9 weeks to flower. A low profile plant that is best for growers with experience growing sativas and more challenging cultivars..
Price from £16.00
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Blackjack seeds will grow into a super hybrid that delivers delicious earthy flavors and a fast flowering period. She has a high resilience to cold and wet weather and works wonderfully during short Summers. Growing Blackjack outdoors is advised as she likes to stay low, making her great for those who need discretion and a fast blooming strain.

She is a feminized strain that displays true hybrid vigor, bold earthy pungent flavors and produces an exhilarating high. A fine blend of indica and sativa genetics that takes between 8–9 weeks to flower.

Black Jack seeds will grow into a low profile plant that is best for growers with experience growing sativas and more challenging cultivars. Overall, a wonderful strain for anyone who spends the time to train their plants, and a superb choice for SCROG.

We created Blackjack cannabis seeds by crossing the super potent indica Black Domina with our Jock Horror. We managed to produce offspring that enhanced the yield and effect of the Jock Horror whilst retaining the high resilience and flavor profile from the Black Domina side.

A fine choice for growers looking for a fast finisher with a high plant resistance that will express a sativa dominance whilst growing.

Blackjack is a low profile hybrid despite her sativa influence, meaning that she will grow medium height, so a fine choice for bedroom growers or those with limited space.

Her growth structure is more Black Domina dominant during the vegetative phase, so will grow with short internodal spacing, resulting in a small stretch once flowering begins.

Plants will be ready to harvest after 8-9 weeks of flowering, where the buds will swell into large sized nugs coated in resin.

Outdoors, Blackjack seeds will grow into short and stocky plants, with a bushy structure and profile. Once flowering starts, the plants will stretch and double in size, making them medium height.

She is a very productive plant that will produce great results in all climates, and will perform especially when in a hot climate such as California.

Thanks to her blend of indica and sativa genetics, Blackjack Feminized will have a high resistance to all types of weather. She can fight off mold and mildew and can endure heat stress with no problems.

Under HID lighting, plants will require 8-9 weeks before they are ready to harvest. Some phenotypes will take longer than others, and we advise inspecting the trichomes after week 8 to make sure you have the optimal harvest window.

Outdoors, Blackjack can take between 56-65 days depending on the climate, location, and pot size. It is recommended to plant the seeds outdoors in Spring time, with a harvest date of early October.

Yields of 450 g/m² (1,5 oz per square foot) can be achieved indoors under HID lighting, and fed nutrients. With longer vegetative times and applied training, it is possible to enhance yields even further.

Outdoors, it is possible to harvest 650 grams (22 oz) per plant can be achieved under the right circumstances. For the best yields possible, keep the plants in a South-facing location.

The final height of the plants once full stretched will be around 100 cm (39 inches) tall, making her a low profile hybrid.

Her growth structure will be similar to the Black Domina parent, and grow with a medium tall central cola, with bushy wide branching.

Blackjack Feminized react very well to topping, tying down and pruning. We advise growing her through a screen for the biggest yields possible, and to maximize your indoor space if limited with room.

Some plants may require staking with bamboo or a net trellis to help support the heavy yielding side branches.

One of the best things about this girl is her aroma and flavor. Blackjack will have an overwhelmingly pungent odor that is a combination of earth, citrus, spices, and lemon.

Her flavors are bold and long-lasting, encouraging a licking of the lips after every pull of a joint. A concoction of pungent, dank, citrus will coat the mouth with a moorish flavor that you will quickly grow to love.

When smoking a joint of Blackjack, the effects will be an immediate sensation of focus, motivation and pure mental energy. Well recommended for busy individuals who need to remain sharp during a working day. Furthermore, an excellent choice for starting the day right with a fresh cup of coffee to stimulate the mind and all senses!

Her THC levels will range between 16-20% with a CBD of 0.1-1% making this strain ideal for morning and daytime use, or those who do not want the effects of powerful indica strains. Medical patients may find Blackjack will improve feelings of well-being, helping lower depression and grow motivation.

More Information
Cup Winner No
Medicinal No
Flowering Type Standard
Yield High
THC Content High (15-20%)
CBD Content Low (0-1%)
Environment Indoor, Outdoor, Greenhouse
Genetics Mainly Sativa
Height Medium
Flowering Time 8-9 WEEKS


FREE 3-5 Day Standard Delivery™

Free standard delivery on your order for delivery within approximately 3-5 days.
(Applies to orders over £50 only)

Royal Mail Signed For™ 1st Class

Royal Mail Signed For 1st Class™ aims to deliver your letter or parcel the next working day however can take up to 3 days - and gives you the added benefits of check online or on your mobile to see where your item is (royal mail website) compensation cover up to £50.

Special Delivery Guaranteed Next Day™

Special Delivery Guaranteed by delivery the next working day. The benefits include end to end tracking and signature on delivery online or via your mobile (royal mail website) compensation cover up to £500 for loss and damagesend items up to 20kg


International Signed For™

For an overseas delivery service you can trust, look no further International Signed For™ mail is available worldwide and travels through a separate and secure network until it leaves the UK . Each item is individually listed and accounted for before being handed over to the airline. Proof of posting and compensation comes as standard, with the option to buy extra compensation up to £500*.

*sometimes £250, depending on the destination.

International Signed For™ items are tracked until they leave the UK when sent by Airmail. Tracking is also available in a number of overseas destinations to delivery.

Delivery aims:

  • to Europe within three to five working days of posting
  • to Rest of World within five to seven working days of posting

* Delivery is in working days and excludes day of posting, Saturdays and Sundays.



Trusted for fast and secure international mail Airsure® receives priority handling in the UK and abroad and is generally a day faster than standard Airmail.

Our aim is to deliver:

  • to Western Europe within two to three working days of posting
  • to Eastern Europe within three to four working days of posting
  • to the rest of the world within six to seven working days of posting.

* Delivery is in working days and excludes day of posting, Saturdays and Sundays.

Note: This service does not guarantee delivery within the timescales indicated. Neither does it offer compensation for delay or for missing tracking information.


Airmail will aim to deliver your mail to:

  • Western Europe within three working days
  • Eastern Europe within five working days
  • major cities worldwide within five working days and other destinations within seven..


You can exchange an unwanted item for a replacement or store credit of the same value if the item is still in the original breeder packet which remains sealed. We will not under any circumstances exchange or replace an open packet. Due to the nature of our products, we cannot give refunds. Kindly note that any items being sent back to us should be sent by recoreded delivery, and the tracking number sent to us by email to [email protected].


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