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black jack auto ( sweet seeds)


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Subcool's thought on Purple Cannabis


Cannabis floral clusters are basically green, but changes may take place later in the season, which alter the color to include various shades. The intense green of chlorophyll usually hides the color of accessory pigments, Chlorophyll starts to loose it’s vibrant green color late in the season and anthocyanin pigments also contained in the tissues are uncovered and the amazing colors are produced at this time. Purple, resulting from anthocyanin accumulation, is extremely common in Cannabis, this color modification is usually triggered by seasonal change, and also can be influenced indoor by a temperature drop of between 20-30 degrees.


This does not mean, however, that Purple is controlled by environment alone and it can be passed on genetically. For purple color to develop upon maturation, a strain must have the genetically controlled metabolic potential to make anthocyanin pigments and be responsiveness to environmental change such as cold nighttime temps. This means a strain can have the genetic potential to change color but if conditions never exist you may never know it.


There are other pigments that effect the color of mature cannabis for example Carotenoid is largely responsible for the yellow, orange, red, and brown colors in buds. I find this effect is much easier to accomplish in Organics and soil but in order to really call a strain Purple it needs to have more than colored outer leaves and the inner buds need to actually be Purple.One aspect that I also find interesting is the purple potency debate, for those that have collected a few plants that produce Purple buds under any conditions like certain Black Russian phenotypes we have noticed something that seems to be consistent. When growing out females of a hybrid that have both color females and non colored females the colored one seems to always be less potent. Now in our case this is to be expected with Sputnik white/green females being more A-13 dominant but I have traveled far and wide and have yet to smoke purple weed that I would consider elite.


Lets look at ways to maximize coloring in your garden.

The first trick to inducing some good color change is what I like to call the “fade” this is when using an organic soil mix you achieve the perfect balance of N-P-K allowing the plant to use up all the available nitrogen and start loosing it’s Chlorophyll and the colored pigments are allowed to bleed through as the green fades. This can be achieved I am sure in Hydro as well but plants react so fast and absorb so well in water that its more normal for a hydro plant to be green and vibrant that multi colored like in soil organics.

The second thing that can really make a huge difference is a large temperature swing between day time and night time temps. The nice thing is with a simple A/c unit and a well built bud room it’s pretty easy to chill a 12x12 room to 60 degrees year round. That same room running 3000 watts will have a day time temperature of between 80-85 degrees making a 25 degree temperature swing. This will easily unlock that fall color hidden inside a strain provided the genetic coding is also there. I have to say from experience it’s a trait of a large percentage of Cannabis that I have grown. Bringing in outside air in colder climates can also be helpful in adding some color as well as keeping bugs in check and a bud room can stand bitter cold if your not worried about reservoir temps.

Last proper application of nutrients is very important if you jack up the N far into bud your not going to see this fading and you may even effect the taste I have found plants that faded to early actually tasted sweeter but then you hurt your yields. Using a good catalyst can also help a lot as the citric acid and sugars seem to speed up the maturation process I currently use sweet leaf at week 4 and week 6. There are many good products and many old timers even make up there own using cane sugar and citric acid but I think the big companies have better research to support there recipes.

copied, pasted & edited from high times article by Subcool


Black Jack Auto is a 3-way cross of Haze ,Jack Herer & S.A.D Auto Which contains "Black Domina", In photo version the 3 way mix is Haze,Jack herer & Black Domina.

It is the Black Domina that is the most genetically disposed to Purpling due to it high anthrocyanin production.


Best way to achive purple buds is buy a strain that is genetically disposed to colouring.

Let it eat up all it's nitrogen to get a good fade allowing the colours to come through,

Significantly lowering the  night time temps will interupt the  nutrient flow & production of chlorophyll in the leaf and the  leaf will fade.  If the leaf contains carotene,  it will change from green to yellow as the chlorophyll disappears. The carbohydrates in the leaves will turn to sugars  & reacts to form anthocyanins pigments. Anthrocyanin will cause the yellowing leaves to turn red/purple.

Low temperatures destroy chlorophyll, and if they stay above freezing, promote the formation of anthocyanins.       

Adding sugar/carbs and citric acid will aid in colouration, it is these sugars that form anthrocyanin, there are many of these products on the market, it isn't really worth trying to make your own as it is too hit and miss.





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