Why does some cannabis turn deep purple, and does the colour mean anything about potency? A look at the plant science — and the common myths.
Purple cannabis is visually striking, and it generates a steady stream of questions at our counters — most often, whether the colour means the product is stronger. The short answer is no. Here is the actual science.
It's About Anthocyanins
The pigments responsible for purple colouration in cannabis are called anthocyanins. These are the same class of compounds — flavonoids — that make blueberries blue, eggplants purple, and red cabbage red. They are common throughout the plant kingdom.
Some cannabis genetics produce anthocyanins in higher concentrations than others. Under certain conditions, especially cooler temperatures during the flowering stage, these pigments become more visible and the plant develops purple, magenta, or bluish tones.
Genetics First, Environment Second
Not every variety can turn purple. The plant must carry the genetic capacity for elevated anthocyanin production. When growers expose such genetics to cooler nighttime temperatures late in flowering, the purple colouration becomes more pronounced. The same genetics grown in consistently warm conditions may finish mostly green.
Does Purple Mean Stronger?
No. This is the most persistent myth about purple cannabis. Potency is determined by cannabinoid content — the THC and CBD numbers printed on the label — not by pigmentation. A bright green flower can have a higher THC percentage than a deep purple one, and frequently does. The lab-tested label is the only reliable indicator of potency.
What Purple Also Doesn't Mean
- Purple is not mold. Mold appears as fuzzy white, grey, or black patches, often with a musty smell. Anthocyanin colouration is a clean, uniform plant pigment.
- Purple is not age. Old, oxidized cannabis turns brownish and brittle. It does not turn vibrant purple.
- Purple is not an indicator of quality, positive or negative. It is simply genetics plus growing conditions.
Assessing Flower Quality, Whatever the Colour
The same criteria apply to green and purple flower alike:
- Labelled cannabinoid content from lab testing
- Aroma — distinct and fresh rather than faint or hay-like
- Moisture — slightly springy, neither dusty-dry nor damp
- Trim and structure — well-formed buds with visible trichomes
Storage Note
Like terpenes, plant pigments degrade with light and heat exposure. An airtight, opaque container in a cool, dark place preserves both the appearance and the labelled quality of any flower.
Cannabis is for adults 19 and over in British Columbia. If you are curious about the genetics behind any variety on our shelves, staff at any Hive Cannabis location can share the producer's published information.
Sources
Cannabis rules are jurisdiction-specific. The references above apply to British Columbia and Canada.
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