Nothing says “WOW” like some green that isn’t green. So where do those amazing bud colors come from?
Cannabis strains, long before cannabinoid testing, could only be measured with the senses. How did it smell & taste? Bag appeal came from the bud trim and aromas, sure. But what really blows us away every time is color. 93% of shoppers make purchasing decisions based on color and visual appeal. And nothing says “WOW” like some green that isn’t green. So where do those amazing bud colors come from?
Looking for funky colored weed? How about this strain that is literally called The White. Just take a look at that spectacular bright white-colored bud. Talk about living up to your name.
Environment and genetics both play a role in the coloration of a plant. But what exactly causes each variety to look the way it does? What gives Black Cherry Soda its otherworldly color of dark purple with vibrant orange hairs cutting through it like streaks of fire?
Let’s explore the color of cannabis and examine which factors influence its coloration, why some strains are more vibrant than others, and whether purple = potent.
How do genetics influence the color of cannabis?
In order for plants to express vibrant non-green hues, they need the genetic building blocks to do so. These building blocks are called anthocyanins, which are a family of flavonoids that provide purple, red, or blue pigments—these are also found in blueberries, eggplants, red cabbage, concord grapes, violets, and other richly colored plants. Some cannabis strains naturally contain higher levels of anthocyanins than others.
Ever notice some of your favorite strains tend to express the same colors over and over again? Granddaddy Purple, for example, seems to always carry swirls of deep purples and pastel lavenders.
This alternative coloration is indicative of the strain’s predisposition to high anthocyanin levels, and it’s certainly a quality some cannabis breeders attempt to select for and coerce, if only to make us consumers ooh-and-ahh over pretty colors (hence the long line of “purple” strains that includes Purple Kush, Mendocino Purps, Purple Urkle, and many others).
Which marijuana strains tend to turn purple, blue, or red?
Many strains contain a genetic predisposition for high anthocyanin levels, and you’ll often find them under monikers that begin with colors like purple, red, blue, or pink. No, this doesn’t mean these strains will always show off fancy hues, but they have a higher potential of doing so if conditions are right.
Plants with low anthocyanin may produce a different array of colors in the final weeks of flowering, due to another family of molecules called carotenoids. These are responsible for the earthy gold and yellow hues buds can take on before harvest as chlorophyll shuts off.
How does cannabis go from green to purple?
As you might remember from your elementary biology classes, chlorophyll is what gives plants its green color. Chlorophyll is vitally important to the photosynthesis process by which plants absorb sunlight for energy.
As cannabis plants mature, they produce less of the dominant pigment chlorophyll and we begin to see those anthocyanins emerge in a show of purples, reds, and blues. Growers should note that there are specific environmental conditions that trigger the halt of chlorophyll production. We’ll get into that shortly.
What other environmental factors affect the color of cannabis?
Although not all cannabis strains will express purple, blue, or red hues in their lifetime, those equipped with the right genetics may do so under certain environmental conditions. The reason why cannabis produces flavonoids and anthocyanin, researchers have observed, is for protection.
“Flavonoid accumulation [is] involved in many aspects of plant growth,” the study authors wrote, “including pathogen resistance, pigment production, and protection against ultraviolet radiation, which contributes to the growth of pollen and seed coat development.”
Information on anthocyanin production in cannabis is limited. What we do know comes largely from cannabis cultivation experience and studies measuring patterns of anthocyanin production in other vegetation.
First, there’s temperature. Purple, red, and blue hues may appear in response to drops in temperature, since chlorophyll production takes its natural pause in autumn as the days become colder.
Research on other fruits and flowers noted that higher temperatures destroy anthocyanin production. That same study also found that higher pH levels lead to the destruction of anthocyanin pigments, meaning they tend to thrive in more acidic environments.
The pH level determines which pigment the plant takes on:
- Acidic environments tend to induce red and pink coloration
- Purple coloration occurs in neutral pH environments
- Blues become present with higher pH levels
- Yellow is developed in alkaline conditions
The Science of Color
Some strains of cannabis change color as they flower. What’s the secret? Genetics. Anthocyanins are a group of around 400 water-soluble pigment molecules classified as flavonoids. They appear red, blue, or purple according to their pH.
Interestingly, flavonoids are generally yellow, hence the latin root “flavus“, meaning yellow. They also have nothing to do with flavor, being extremely bitter.
The Fall Effect
Think of the tree leaves in fall. As temperatures drop, they change from green to red, orange, yellow, or gold. Cannabis doesn’t produce the colors until the latter half of the flowering stage, with a few exceptions. Once the green fades, they can come forth and shine.
Temperature plays a vital role, as cooler temperatures inhibit chlorophyll production. Chlorophyll, you might remember from 6th-grade science, is the plant component vital to photosynthesis.
For cannabis, depending on the lineage of the strain, certain other colors will appear when you drop the temp and the light cycle shortens, mimicking the change in season.
The ideal range to grow cannabis is a pH of 5.5-6.5. But during flowering, you can lean one way or another to enhance or minimize certain anthocyanins, bringing out certain colors.
Purple and Blue Strains
The many strains of cannabis come with different cannabinoid ratios, flavor profiles, and anthocyanins. The most prominent variation to green cannabis is purple. Strains like Purple Urkle, Grandaddy Purple, and many others easily produce that pigment.
Certain strains have so much that you don’t even need to drop temperatures to see the change, as the plant naturally starts to lose chlorophyll at the end of its life. Purple Orangutan has some of the strongest blue and purple hues in the world.
Purple hues come to the fore in more neutral pH environments. Blues also enjoy higher pH levels than most cannabis strains.
Red and Pink Strains
Red hairs show up more frequently today, but actually red buds and leaves are not nearly as common. For truly ruby herb, some strains that carry dominant red tones such as Pink Flower Shaman, pictured above, you will have to do some searching.
Predator Pink expresses some phenotypes with actual pink and fuchsia hues. Don’t go buying every strain with red or pink in the name, however. Most of the time, this refers either to the hairs or flavor accents, like pink lemonade or grapefruit.
You can also cheat a little changing plant leaves and buds a bit red by manipulating nutrients. Phosphorus deficiencies can cause this, but it won’t be as pretty as the real thing.
Yellow and Orange Strains
Carotenoids give cannabis those citrusy hues of yellow, gold, and orange. To get these colors, you want more alkaline conditions. If these colors are predominant in the plant, they will naturally come out as the flowering phase comes to an end and chlorophyll starts to fade.
Orange will mostly affect the hairs and buds, such as Olive Oyl, Kandy Skunk, and some phenos of Alien OG. Yellow strains include Wicked OG, Grapefruit, and Lemon Kush, of course, which all taste great in the PAX 3.
There are some rare strains that turn so dark that they appear black. The origin of these genetics goes back to Vietnamese landraces, I.E. Vietnamese Black. All other strains derived from hybrids, such as Black Willy and Black Tuna, share both the signature ebony buds and leaves.
In addition, black strains are noted for their intense psychedelic, cerebral highs. If you want visuals, this lineage is a surefire hit. The inky appearance comes from an overabundance of all colors in the leaves. With warmer temperatures, the dark reds and purples get replaced with lighter reds and golds in some cases.
Other ways to increase bud colors
Anthocyanins can be present in the vacuoles of the cells in plant tissues, leaves, and flowers. Sometimes, they even present in the trichomes themselves. They also act to attract pollinating creatures like butterflies and bees, while deterring pests that might snack on them or lay their eggs by tricking them to think the plant is unhealthy.
Besides pH and temperature, using LED lights with specific spectrums can enhance the production of anthocyanins in the tissues of cannabis. They serve as “sunscreen” for plants, so stressing them with more UV light can make the plant produce more, enhancing the color.
Color vs potency
A common misconception is that strains with bold color are more potent. The truth is that color has nothing to do with potency, just bag appeal. However, anthocyanins are known to act as powerful antioxidants and are also thought to have analgesic, anti-inflammatory, and neuroprotective properties.
Research suggests that some anthocyanins have a selective affinity for either CB1 or CB2 receptors, depending on the type.
So while the presence of anthocyanins doesn’t change the potency of cannabinoids like THC, it might give the strain an added entourage effect on health.
Other plants high in these molecules include blackberries, blueberries, raspberries, goji berries, blood oranges, and cranberries. Cranberries especially are touted for their powerful antioxidant properties, due to anthocyanins.