top of page

Anthocyanin in Weed - What It Does & Why It Matters

We often think of weed, and most other plants, as green; however, when anthocyanin pigment molecules are present, purple cannabis strains can develop. The anthocyanin pigments that turn weed purple aren't exclusive to the cannabis plant; they are also present in other red, blue, and purple plants like grapes, blueberries, and onions.


Most plants, including green cannabis, have naturally low levels of these pigments, but in certain circumstances, such as high levels of direct sunlight, plants with certain genes can produce higher levels of anthocyanins. This leads them to turn purple. For lovers of purple strains such as Purple Haze, or for people who have a license to grow their own purple weed, knowing the optimal conditions for colored weed plants can help you achieve the desired color.

What are Anthocyanins?

The word "anthocyanin" is a mixture of two Greek words meaning "flower" (anthos) and "blue" (kuanos). Though anthocyanin-rich cannabis strains are usually known for their purple coloring, anthocyanins in cannabis plants and many other plants can present themselves in a variety of colors, from deep reds to purple hues.


Scientifically, anthocyanins are pigment molecules that belong to a larger class of compounds called flavonoids. These colored compounds can be found in the stems, leaves, flowers, fruit, and even the roots of plants that contain them.

What Is the Function of Anthocyanins in Plants?

There is much debate in the scientific community about what exactly the function of anthocyanins in plants is, despite extensive research on their importance and role. Various environmental factors such as nutrition, drought, light, and temperature affect the accumulation of anthocyanins in many plant species. Anthocyanins can help plants cope with certain environmental factors by:

  • Working as sunscreens and antioxidants

  • Encouraging pollination by attracting insects with their vivid colors

  • Delaying leaf deterioration: Plants growing in nutrient-deficient soil can suffer from deterioration over time. Anthocyanins are thought to delay this deterioration (Peng et al., 2007a, Peng et al., 2007b, Peng et al., 2008).

Are Purple Strains Better than Other Strains?

There isn't any scientific evidence to suggest that purple cannabis is better or different from any other type of cannabis simply because of its color. Purple cannabis is attractive and eye-catching, making it appealing to some consumers. Others like purple strains purely because of their effects.


Ultimately, the potency, taste, smell, and medicinal benefits of a weed strain are due to its chemical composition rather than its color. Lovers of Purple Haze, Sour Grapes, or any other purple cannabis strains can thank the cannabinoids and terpenes in these strains rather than the color for these strains’ effects.

Are Purple Strains Healthier?

Though purple fruits such as blueberries contain high concentrations of antioxidants, you would have to consume an excessive number of purple cannabis buds to get any benefit from the antioxidants. This, of course, isn't recommendable!

What Possible Medicinal Properties Do Purple Strains Offer?

Different strains of purple weed offer different effects. Some common purple weed strains and their medicinal benefits include:

Purple Kush

Anecdotal evidence suggests that Purple Kush can help to abate bouts of extreme nausea and stimulate appetite (making it a good strain for chemotherapy-related nausea and appetite loss), and can significantly improve symptoms of insomnia and chronic pain. Consumers of this strain also claim that Purple Kush can help with symptoms of depression, stress, and anxiety.

Purple Haze

Purple Haze is renowned for its mood-changing effects. For that reason, this strain is consumed by patients who suffer from anxiety, panic attacks, depression, and chronic fatigue syndrome.

Granddaddy Purple

Granddaddy Purple is most commonly used for relaxation and inducing sleep, so it could be a good option for patients suffering from stress or anxiety. Some suggest that it's also effective in managing depression and chronic pain, and that it can stimulate appetite.

What Conditions Do You Need to Grow Purple Marijuana?

Patients in Arizona and many other states where medical marijuana is legal have the right to grow their own marijuana plants at home (make sure you renew your medical marijuana card before it expires to hold on to any patient-only growing rights). For these people, making cannabis leaves turn purple is a question of science.

1. Choose the Right Strain

Changing the conditions alone isn't enough to change the color of your plants; genetic makeup is the most important factor in determining the color of your cannabis. Purple strains are specifically bred for their color, so choose your strain carefully, taking into account the THC and CBD content you are looking for as well as the hue.

2. Adjust Your Temperatures

Plants only turn purple after they've finished their vegetative growth and begun the flowering phase. At this point, you can start adjusting the conditions by dropping nighttime temperatures. Because colder temperatures can encourage your plants to produce more anthocyanins, there should be a difference of 50-59 ºF (10-15 ºC) between daytime and nighttime temperatures.

3. Strong, Direct Light

Intense, direct light may help to produce purple tones. The purple color will be more noticeable on the parts of the plant that are exposed to the most direct light, and some strains may react more or less to differing levels of light.

4. The pH at the Roots

The pH in the soil you use might affect the bud color produced. There is some anecdotal evidence to suggest that buds are more likely to produce a more vivid purple color if the pH of the soil is less than 6. However, a low pH can also cause brown spots to form, so you may find that cultivating purple cannabis is largely a matter of trial and error.

Purple Cannabis May Offer Subtle Health Benefits, but its Appeal Is Largely Cosmetic

Some purple cannabis strains may offer medicinal benefits for things like nausea, appetite, mood, pain, and sleep, but the appeal of the blue and purple pigments is mostly aesthetic. The medicinal properties of a given strain are due to its unique cannabinoid and terpene profile rather than the presence or absence of pigment molecules.


When looking for cannabis strains with properties that could help to treat a specific condition, check the THC and CBD content and research any potential benefits that certain purple strains might offer. If you have permission to grow your own cannabis at home, implementing the growing tips we mentioned above could help you bring out the color in any anthocyanin-rich strains you choose.

Recent Posts

bottom of page