Weed porn spreads in magazines usually feature one plant with insanely purple flowers. Chemovars or strains like Purple Pineberry, Grape Ape, Grand Daddy Purp, Mile High Purp, Purple Kush, and KF7 can more closely resemble violets than they do cannabis. How does cannabis get such a wide range of colors? And how can a growers cultivate these hues in their own plants?
Cannabis Chemistry: Anthocyanins
The cannabis plant, like any other plant, contains several classes of chemicals. Cannabinoids like THC and CBD remain the most famous, but terpenoids like pinene and myrcene are gaining popularity as the public learns more about cannabis. Flavonoids and polyphenols are additional compound categories slowly coming to the forefront as researchers continue to crack cannabis’s biochemical profiles.
The purple color found in cannabis comes from another category of molecules called anthocyanins. Technically a blue-purple pigment, anthocynanins are responsible for the full range of cooler colors displayed by cannabis plants, from blue to violet. Other purply plants, such as plums and eggplants, also produce anthocyanins. Additionally, these compounds may confer health benefits, such as antimicrobial or antioxidative properties.
The green in cannabis comes from chlorophyll — the little verdant organelles that generate the plant’s energy from sunlight. Anthocyanins naturally reside in all cannabis plants, but the presence of chlorophyll often buries the purple light that would otherwise reflect from the flowers.
Because of chlorophyll’s purple-masking effects, anthocyanins become most visible after the curing process breaks down some of the buds’ chlorophyll. Growers can also force the coloring by fiddling with temperatures in a grow room.
How to Grow Weed So Purple It’s Practically Black?
Black weed? That’s a real thing. BC Bud Depot in Canada sells a plant called The Black known for its unusually dark, deep violet shade. Although The Black’s lineage is a mystery, it likely doesn’t grow this way on its own.
In fact, it’s possible to cultivate purply cannabis plants in a way that minimizes chlorophyll production. To do this, simply lower the temperature during the 12/12 light cycle to 10°C (50°F) during the dark phase.
By lowering the temperature, the plant behaves as if autumn just started. Like brown and red maple leaves littering the streets in the fall, triggering a false autumn forces cannabis to cease chlorophyll production. If the plant already produced ample amounts of anthocyanin – strains such as Black Widow, Black Mamba, Black Diesel, or The Black – with the green gone, it will eventually appear black due to the anthocyanin concentration.
For growers looking for feeds or nutrients to jack-up anthocyanin production, there aren’t any. Only climate changes and genetics can get Mary Jane looking so regal.
Follow Randy Robinson on Twitter