How to Grow Purple Cannabis
Every grower has fantasised about harvesting big, purple buds at home. But what exactly can you do to manipulate the colour of your weed?
Purple cannabis certainly does exist, but there’s a right way to turn your pot purple, and a wrong way.
HOW TO GROW PURPLE CANNABIS
Purple weed is real eye candy. And while there are many rumours circulating the internet about how to grow purple cannabis at home, there are really only two variables that you can play with to manipulate the colour of your weed. Keep reading to find out what they are.
WHAT CAUSES CANNABIS TO TURN PURPLE?
All plants have naturally occurring pigments. The most dominant pigment in most plants (including cannabis) is chlorophyll, which, apart from helping plants photosynthesise, also gives them their green colour.
However, plants also have many other active pigments, including carotenoids and anthocyanins. In the absence of chlorophyll, plants may use pigments like anthocyanins to absorb sunlight and photosynthesise. Unlike chlorophyll, anthocyanins naturally absorb all wavelengths from the sun except those in the indigo spectrum, which is what gives plants their purple colour.
Hence, purple cannabis plants (or any purple plant for that matter) get their colour because the dominant pigment in their leaves and flowers are anthocyanins, rather than chlorophyll.
WHAT PARTS OF CANNABIS CAN TURN PURPLE?
There are four main parts of your cannabis plant that can turn purple:
• Pistils: Pistils are the fine hairs that pop out of your buds, letting you know they’re female. Pistils generally start off a creamy white colour and turn orange/red/brown as plants mature. However, it is possible for your plant’s pistils to turn pink or purple, and this colour will remain after you harvest, dry, and cure your buds.
• Calyxes: Calyxes are the small pods that make up your buds. Cannabis flowers are actually made up of hundreds of these small calyxes stacked on top of one another. As the flowers mature, the calyxes open and reveal their pistils, which are designed to catch pollen from male cannabis plants.
• Leaves: The fan and sugar leaves of your cannabis plant can also turn purple. However, they usually won’t have a large effect on the final colour of your buds, as you’ll likely trim away most of the leaves during your post-harvest work.
• Trichomes: Trichomes are the tiny crystals that cover your buds. While they usually start off clear and become opaque and then amber later on, it is possible for them to turn purple, too.
THE WRONG WAYS TO TURN YOUR POT PURPLE
Many people mistakenly believe that the best way to turn cannabis purple is to deprive their plants of oxygen. However, depriving your plants of oxygen, carbon dioxide, or any other gas will not improve your chances of harvesting purple buds. Feeding your plants more nitrogen also won’t change the colour of your plants, at least not unless you overdo it and end up burning them to a crispy shade of brown.
Some growers also use food colouring to dye their plants. And while it might work, we definitely do not recommend trying it. Finally, changing your plant’s light cycle, watering schedule, or grow medium also won’t increase its chances of turning purple, nor will yelling, screaming, or singing to your plants.
THE RIGHT WAYS TO TURN YOUR PLANTS PURPLE
Now that you know how NOT to go about growing purple weed, here are a few pointers to help you maximise your chances of harvesting some eye-catching purple buds this season:
1: START WITH THE RIGHT GENETICS
Genetics are going to have the biggest impact on the final colour of your plants. So, if you’re set on growing purple weed, shop around for purple strains, as they’ll have been specifically bred for their unique colour. Remember that your buds are going to lose some colour after trimming, so opt for strains with the most vibrant purple pigmentation you can find.
Keep reading through to the end of this article for some top recommendations on purple strains to grow at home.
2: ADJUST YOUR TEMPERATURES
While you might be eager to watch your plants turn purple, this will usually only happen once they’ve finished vegetative growth and start flowering. Once your plants have entered their flowering stage, try dropping your nighttime temperatures. Colder temperatures cause chlorophyll to break down and can encourage your plants to produce more anthocyanins. Ideally, you’ll want there to be a difference of 10–15°C between your daytime and nighttime temperatures.
OTHER WAYS TO GROW PURPLE WEED
There are some other ways to manipulate the colour of your plants. Most of these techniques, however, involve depriving your plants of certain nutrients, which, of course, we do not recommend doing. Even if you are able to achieve some purple colouration using these alternative methods, it will likely be to the detriment of quality, flavour, and potency.
GENETICS: THE #1 REASON WEED TURNS PURPLE
Remember, the two main factors affecting the colour of your cannabis plants are genetics and temperature. If you’re really set on growing purple weed, make sure to invest in the right genetics from the get-go.
At Royal Queen Seeds, our expert breeders have bred some killer purple strains. Make sure to check them out and add a splash of colour to your next harvest:
Purple Queen is an almost pure indica variety bred from Hindu Kush and Purple Afghani genetics. She flowers over 9–11 weeks and produces big, purple buds with a uniquely pungent aroma that combines hints of both pine and fuel. Purple Queen also boasts a THC concentration of up to 22% and produces a nice, relaxing body stone that’s perfect for whenever you need to unwind and relax.
Perhaps you've seen brilliant purple bud. Perhaps you've even accidentally grown it. Now, you'd like to do it on purpose. Here is the ultimate guide to making your bud glow with that unique purple hue.
Why Does Weed Turn Purple? Truths and Myths about Purple Cannabis
Thursday April 5, 2018
I n these modern times of cannabis consumption bad information still runs rampant, and few things in the world of weed have as large a mythic standing as purple bud. This seemingly simple topic can actually be a bit convoluted, starting with, what is purple bud? The short answer is cannabis flowers that exhibit a darker, purple-tinged hue. However, it is not always the shade most people think of as “purple.”
Purple cannabis can be a tricky concept. Just stop for a moment and contemplate the timeless line, “roses are red, violets are blue.” A modern sensibility would correct that the color of violets is none other than violet. Similarly, purple weed is not always “purple.” It can have a wide range of presentation, from dark green to even black.
Why is Some Cannabis Purple?
Consider that what we call a blueberry is also usually quite purple. This is because the very thing that makes blueberries “blue” is the same as what makes purple nugs “purple,” anthocyanins. Anthocyanins are water-soluble pigments present in many plants. Despite the “cyan” in “Anthocyanins” referring to their blue nature, these molecules occur in a range of colors from red to purple to dark blue, or black, depending on pH level.
Anthocyanins are part of a larger class of substances known as flavonoids, which aside from how the name sounds, have very little to do with flavor (and are astringent to the taste). In fact, the “flav” in flavonoids comes the Greek word for yellow, flavus.
This can be a bit linguistically confusing; a blue-named class of molecules that presents as red or purple is a subset of a class of yellow-named molecules. It begins to make sense when we consider that a complex interaction of anthocyanins and other flavonoids is what causes leaves to change their color among such a brilliant spectrum in the fall.
When cannabis presents as purple, we are seeing a similar phenomenon as fall leaves, allowing purple bud to have a wide spectrum as well. Like other plants for cannabis, colors, and changes in color, have purpose. The stressed plant is changing pigment in order to achieve a goal before wilting in the cold, such as conserving energy or increasing chances for pollination.
For cannabis strains, the ability to present darker pigments, and to what degree, is wholly dependent on the plant’s genetics.
Without a predisposition to purpling, a given strain cannot be induced to turn purple. Certain strains will have more naturally occurring anthocyanins than others, and when switching to the “winter” cycle of flowering, will start to express those purple pigments innately according to their genetic predisposition interacting with the unique chemical and environmental factors in which the plant is grown.
Is Purple Marijuana Better?
Visual appeal aside, is there reason to believe that these royal-toned flowers are better than the green hues more common to the plant? The science leans towards no.
According to the European Food Safety Authority, there is no substantive evidence anthocyanins have any effect on human biology or diseases – though they contain a higher concentration of anti-oxidants, which would theoretically only be beneficial if one were eating buds. There is some minor proven correlation to anthocyanins as an anti-inflammatory, but again, would probably be more active if ingested. Seeking a strain with higher CBD content would be a better source for anti-inflammatory effects than purple hue.
In general, purple bud has a tendency for lower THC content than its greener counterparts. That’s not to say high-THC purple is not possible, we’re sure we’ve all seen or smoked an exception to the rule. That is because most purple bud that we see today is not a result of stressing the plant, but genetics.
To better understand this connection, I spoke with veteran grower and concentrate connoisseur Matt Gosling about the popularity of purple cannabis. While purple bud can be fantastic, he explained, it’s usually due to good breeding and genetics, and not much else.
“Purples are memorable. If you have a good high with purple bud, it’s going to stand out. Then if you’re a grower and you have the ability to then reinforce those genetics you’re going to, and it propagates itself from there.”
Anything beyond breeding could detriment the plant. “Any energy the plant spends pushing out that purple pigment is going to be drawn from somewhere else and is going to hurt overall. It’s just not worth risking the quality for a chance a slightly better bag appeal.”
Myths about Purple Weed
Some people believe that there are growers out there who bring out purple hues by manipulating the plant, however, the prevalence of such practices seems to largely be a myth. I rattled off a list of alleged techniques for inducing purple bud to Matt, such as affecting nutrient levels or flash freezing, and he quickly declared them bunk.
That’s not to say attempts at purpling don’t occur at all, “I’ve seen some people use ice water to do their flush,” he told me, “some other tweaking with light timing, but I don’t recommend any of it.”
In speaking with growers, budtenders, flower reviewers and other cannabis journalists, the consensus among the industry is to treat each harvest as unique–smoke what appeals to you. If the effects of purple strain are appealing, go for it.
Furthermore, no one is wrong to feel that the visual appeal of a flower can enhance the smoking experience. However, ultimately, the mere presence of the pigment is unrelated to the resulting effects. If the flower is good, by all means smoke it, in any spectrum of the rainbow.
What are your thoughts on purple weed? Do you find it to be better than green cannabis?
Matt Mongelia holds an MFA in writing from The School of the Art Institute of Chicago. He has worked in the cannabis industry in various roles for 4 years, from dispensaries, production and retail to events, content and marketing. He is a writer for the comic Dark Beach, and has previously covered music and cultural content for SOL REPUBLIC.
Everyone cannabis enthusiast has a place in their heart for purple weed. Learn about why cannabis turns purple and some of the truths and myths behind it.