Have you ever seen purple cannabis and thought, "Whoa - that looks gorgeous!"?

Growing vibrant purple cannabis is an exciting way for gardeners to expand their skills and show off exotic plants. But it does take specific techniques. You can't just turn any weed plant purple.

In this guide, we'll bust myths about purple weed and explain how to really achieve that stunning color. With the right genetics and optimized grow conditions, you too can cultivate beautiful purple weed that will impress fellow enthusiasts. 

Overview: What is Purple Cannabis? 

Purple weed gets its awesome colors from compounds called anthocyanins. These are water-soluble pigments that protect the cannabis plant.

When exposed to low pH levels, anthocyanins turn purple.

A lot of popular weed strains - like Purple Urkle - naturally produce high levels of anthocyanins. 

Why Do Cannabis Plants Turn Purple?

Don't worry; the purple color doesn't mean your plants have nutrient problems. It's actually genetic!

The purple color is influenced by growing conditions, too. Factors like cool temperatures, high humidity, and UV light exposure can ramp up anthocyanin production in purple strains, making their color even more vivid.

Growers can optimize the environment to encourage purple strains to fully show their colors.

When you dial it in just right, the buds will develop rich violet, blue, and lavender pigments in the leaves, calyxes, and trichomes. With the right genetics and conditions, you can maximize anthocyanins and grow the most stunning purple cannabis.

Which Parts of the Plant Turn Purple?

Contrary to popular belief, the whole cannabis plant doesn't turn purple. The main parts of the plant that develop the color are the:

  • Pistils
  • Calyxes
  • Trichomes
  • Leaves

Pistils often grow orange/brown but can turn pink and purple.

Purple calyxes directly color the buds, so strains with extensive purple calyxes produce deeply hued purple weed.

Some strains also develop purple-tinted trichomes for added vibrant color.

While fan leaves and sugar leaves can become intensely purple, most of this leaf color is trimmed off, so it doesn't affect the final bud appearance much.

To maximize the purple bud color, seek genetics with purple expressed in the calyxes and trichomes versus only the leaves.

How to Grow Purple Cannabis Indoors

So, how does one actually grow purple cannabis? There are two ways:

Step 1. Use Naturally Purple Strains

The best way to grow vibrant purple weed is to start with genetics that naturally produces high levels of anthocyanins - the purple pigments.

Popular naturally purple strains include Granddaddy Purple and Purple Kush. There are also strains specifically bred to be ultra purple, like Purple Punch. Choose one of these "purp" varieties to let genetics do some of the work.

Then, you can use targeted growing techniques to maximize the purple hues, like:

  • Keep the grow area temps cooler, around 60-70°F, and lower them further near harvest time to spur more anthos.
  • Give plants full darkness for 12+ hours overnight. Extended dark periods encourage purpling.
  • Maintain humidity around 60% for maximum color. Let temps dip significantly into the 50°F range each night to trigger anthocyanins.
  • Cut back on nutrients in late flowering, too, to encourage purples.
  • Use blue-leaning LEDs and metal halides over red/orange high-pressure sodium lights.
  • Allow the medium to dry out between waterings to stress the plants in a productive way.

Overall, be sure to avoid steady conditions - fluctuations in the environment help bring out the purple color. Note that higher elevations increase anthocyanins thanks to lower atmospheric pressure.

Follow this blueprint to amplify purple strains' natural potential for vivid color.

Step 2. Manipulate Grow Room Conditions to Turn Strain Purple

You can turn regular weed strains vibrant purple by carefully controlling the indoor grow environment. Follow these steps:

  1. Dial in cooler temperatures year-round. Keep your grow room around 60-70°F using standalone AC units or central cooling. Let the area get significantly colder at night, dropping into the 50°F range.
  2. Use humidifiers to maintain 60%+ humidity.
  3. Switch between LED and HPS lighting, using more blue-leaning LEDs to encourage anthocyanins.
  4. Avoid intense lighting that diminishes purpling.
  5. Give plants 12+ hours of uninterrupted darkness each night using blackout curtains. 

If you have the budget for it, consider investing in automated environment controls. They make optimizing conditions for purple strains easy. Monitor conditions closely and adjust quickly to maintain the ideal levels.

The key is creating a big difference between day and night temperatures. Aim for 15°F cooler nights. Just like trees changing color in fall, the cold nights cause cannabis plants to stop making as much green chlorophyll and increase production of anthocyanin pigments, turning foliage purple.

If you're growing weed during warmer months, you may need an indoor setup to properly drop those night temps low enough. With some simple temperature manipulation, you can turn almost any cannabis strain deep purple for an eye-catching look.

Step 3. Cut & Process for Purple Preservation

Proper harvesting and drying techniques preserve those coveted purple and violet tones in your cannabis. Here's how you can cut and process your weed to preserve their vibrancy:

  • Harvest plants when most trichomes are still cloudy - before the amber hues set in.
  • Use a wet trimming process to keep the fragile trichome heads with purple pigments intact.
  • Slow dry the buds over 14+ days at around 60°F and 60% humidity. Quick drying will degrade those fragile anthocyanins.
  • Keep buds in complete darkness while drying and curing. Light exposure breaks down the light-sensitive purple pigments.
  • Use drying racks for evenly controlled conditions all around the buds.
  • After drying, jar cure in the dark for 4+ weeks at 60°F and 60% RH to fully develop purples.
  • Avoid over-handling to prevent knocking off colorful resin glands.
  • Pack cured buds very loosely to prevent crushing the purple calyxes and leaves.
  • For storage, keep at 55-60°F with ~60% humidity to retain that rich purple color.

Remember to always process and store buds in complete darkness to protect the anthocyanins. And use opaque, light-blocking packaging when shipping your purple pot to dispensaries or customers.

Follow this careful process, and your buds will keep their colorful visage.

Growing Purple Cannabis: What NOT To Do

It may be tempting to experiment with ]unconventional methods to induce a vibrant purple hue in your plants. But just know that most - if not all - of these techniques are ineffective. They can even compromise the quality and potency of the plant.

Techniques like depriving the weed plant of nutrients, oxygen, or other gases should be avoided.

Likewise, do not infuse your plants with excessive nitrogen or food dye to alter their color.

Lastly, some people may claim that singing can influence the cannabis plant's color. Please don't believe them. Only genetics and environmental conditions can alter cannabis colors.

The best way to achieve a vibrant purple color in cannabis is to either select strains with the appropriate genetics or to manage cooler temperatures during growth. These approaches take out the stress on you and the plants you're growing.

Tips to Maximize Purple Cannabis

Let's recap and simplify the best ways to grow purple cannabis:

Temperature & Humidity

  • Day Grow Room Temperature: 60°F - 70°F | 15°C - 21°C
  • Night Grow Room Temperature: 51°F - 59°F | 
  • Grow Room Humidity: 60%+

Lighting

  • Main Lighting: Blue-leaning LEDs
  • Secondary Lighting: LED & HPS (switch between the two)
  • Blackout Period: 12+ Hours/Night 
  • Avoid: Intense Lighting

Frequently Asked Questions

Is purple cannabis better than regular green cannabis?

No, not all purple cannabis strains are weaker than regular weed. Potent varieties like Granddaddy Purple and Pinkman Goo contain plenty of cannabinoids despite their purple hues.

Weed potency depends on genetics, not color. 

Purple cannabis plants get their vibrance from anthocyanin pigments. With the right genetics, temperatures, and humidity levels, anyone can cultivate a stunning purple yield. Basic gardening skills help, sure.

However, selecting purple genetics and optimizing the grow room environment is key to successfully growing these colorful cannabis plants.

What's the difference between green and purple buds?

There is no difference! Green and purple weed may look totally different, but they're both still cannabis plants. Perhaps the only thing that sets the two apart (aside from color) is the number of anthocyanins.

Purple varieties naturally produce more anthocyanins compared to other varieties. That's the pigment that makes blueberries blue. These compounds turn vivid purple in cool conditions. So purple strains like Purple Kush contain extra anthocyanins that express more color.

But green and purple cannabis have the same cannabinoids and effects. Purple weed just has an exotic, aesthetic look from those anthocyanin pigments responding to chilly temps.

Can I use purple dye to turn my cannabis plants purple?

No, you absolutely should not use any sort of colored dye on your plants. It can be tempting to use food coloring to turn your green buds purple, but this will negatively affect your plants' health - and potentially yours.

Those dyes contain chemicals that can interfere with the natural potency or terpenes of the cannabis. Purple weed gets its color naturally from genetics and chilly temps.

Save the dye for Easter eggs.

Conclusion

Growing vibrant purple cannabis can be done without using extreme deprivation techniques or colored dye. Just choose the right genetics, optimize the environment, and carefully process and store your buds. You'll end up with a beautiful purple yield.