The Science Behind Cannabis Plants Turning Purple

If you have experience with cannabis, you may have noticed that some cannabis plants turn purple after a while. But, have you ever wondered what the science is behind that?

There can be environmental reasons and genetics at play, but there is also the question of whether purple cannabis is more potent.

Genetics

Genetics probably play the most significant role in turning cannabis plants purple. Scientifically speaking, a group of flavonoids called “anthocyanins” provide either red, blue or purple pigments in plants. They can also be found in many different purple and red vegetables and fruits (eggplants and blueberries, for example). It is essential to remember that, no matter what you do, if anthocyanins in the plant are low, then the chance of a cannabis plant turning purple is also low.

However, the color purple doesn't automatically mean that the plant is more potent. Purple plants look more attractive to the customers, which has made a considerable number of cannabis breeders go for the purple ones more often. Thus the perceived value makes anthocyanins a bonus when you're taking a closer look at cannabis genetics.

The Science

Chemistry has taught us that plants are green because of chlorophyll, which helps with photosynthesis by allowing the plant to convert sunlight to energy. So, how is that purple hue in cannabis formed? Over the lifecycle of the cannabis plant, the production of chlorophyll reduces. This allows other compounds to manifest. In the case of purple cannabis strains, we're referring to anthocyanins - the green pigmentation associated with chlorophyll begins to slowly turn to blues, reds, and purples of anthocyanins.

The Role of the Environment

Did you know that anthocyanins increase in production when the plant senses that it is in danger? Scientists have noticed that in the colder Autumn months, the chlorophyll production in plants reduces, and flavonoid accumulation starts happening. In strains with a pre-disposition for anthocyanins, this leads to color-changing.

Anthocyanins don't go well with high temperatures; it destroys them! This means that the myth about "purple cannabis coming from the cold north" is true. PH levels also play a significant role, as it is indicative of the pigmentation of the plant. Acidic environments tend to produce more reds and yellows; purple results from pH neutrality, and blues tend to express themselves at higher pH levels.

Potency

Science has shown that anthocyanins could impede THC development. This means that the widespread belief that purple cannabis plant is more potent is not true at all.

But this doesn't mean they are not potent at all, nor even less potent, for that matter. We need to understand that THC development depends on many other environmental and genetic factors as well.