How to Grow Purple Marijuana | The Full Guide

Cannabis isn’t just about getting high. It isn’t only about the taste or the smell. Smoking quality pot is also about how it looks. And the better it looks, the more you are probably going to like it.

Think about this – you wouldn’t go to your local grocery and pick up some fruit that looks bad, or buy some ground beef that looks like it’s been sitting in the Vegas sun for a week straight, would you?

It’s human nature. We want to get our money’s worth, and we tend to always look for the best. And the same goes with weed; if we were to take two similar strains and apply some eye-catching “color” to one of them, 9 out of 10 people would probably purchase the colored one rather, even though in reality they have the same potency and will probably have the same effect. (Hell, a lot of people even pay more for colored/purple cannabis buds).

In this article, in addition to explaining how to grow purple weed, we explain how (and why) weed turns purple in the first place, what it does to the THC/resin content, and what it means in terms of the overall health of the plant.

Purple Marijuana: What, Why, and How…

There are many reasons people color their cannabis. Some do it for fun, some to make it look more appealing, and for others, it’s actually a way to bump up their prices (although in just a little bit we’ll talk about why this is usually a complete scam).

Over the years, in fact, we’ve heard of quite a few ways to get your buds purple. We’ve even seen people use purple food coloring to dye the plant — TERRIBLE!

Ultimately, many people mistakenly believe that the best way to turn cannabis purple is to “stop it from breathing.” They deprive the plant of Oxygen, carbon dioxide, and other gases, trying to “suffocate” the photosynthetic process in order for it to turn purple. These methods are not advised as they will reduce the overall quality of the weed, eventually killing it off completely.

Purple Cannabis

Whatever your motivation for coloring or growing purple weed, this step-by-step guide will help you turn that plain old cannabis seed into something truly unique – even “miraculous” by some people’s standards!

First, though, let’s talk a little bit about how a purple marijuana plant even exists, and what in means in terms of the overall health and quality of the plant.

Is Purple Weed Better than “Green Weed?”

It’s hard to believe, but there are indeed a lot of cannabis growers/sellers (and even some dispensaries) out there that will tell their customers purple weed is “better” or “more potent” than its standard green counterpoint. Without going into a whole scientific debate, this is just flat-out wrong.

Basically, all plants have actively-functioning pigments that are used to capture energy from sunlight. This energy is of course used to help drive photosynthesis, which is the molecular process that allows a plant to grow, develop, and mature.

Why Is Weed Green Anyway?

In most plants (including marijuana), the dominant pigment is chlorophyll. Chlorophyll is extremely efficient at capturing light energy, which is evident in the fact that it absorbs nearly every wavelength of the visible light spectrum. In fact, the only wavelength it does NOT absorb is those in the “green” spectrum (about 530-560 nanometers), hence the reason why most plants appear green to the human eye.

However, most plants have functional pigments other than chlorophyll. In fact, in the absence of chlorophyll, many plants will use anthocyanin – another pigment – to capture sunlight energy. If you remember the old ROYGBIV acronym from your high school science days, you’ll know that visible wavelengths from the sun can appear to the human eye in the form of Red, Orange, Yellow, Green, Blue, Indigo, and Violet. Unlike chlorophyll, anthocyanin absorbs all wavelengths except for those in the indigo/violet spectrum. In other words, it reflects back violet light, making the plant look purple to the human eye.

Simply put, purple marijuana plants are purple because the dominant pigment is anthocyanin rather than chlorophyll.

So what does this all mean in terms of the overall health and potency of the weed – is purple weed more potent than “regular” green weed? Hardly. In fact, it’s just the opposite.

Purple Weed vs. Green

On the visible light spectrum, “purple light” actually contains the highest energy (at roughly 400-430 nanometers). Since purple weed plants are NOT absorbing this high-energy light but instead reflecting it back into the atmosphere, they are NOT utilizing the maximum amount of energy as possible. In other words, purple weed is LESS potent than green weed.

There are probably loads of growers and “industry experts” that would disagree with this statement, but there’s simply no arguing with the science. If light energy from the sun is used to mature the marijuana plant (i.e. grow the THC-containing buds), the more energy that is available will ultimately result in the ability to produce more potent flowers. If a plant is NOT absorbing the highest-energy light (purple light), then it is NOT going to be able to develop and mature to its maximum potential.

Related article

Granted, there are other things (like genetics) that come in to play as well, but generally speaking, purple marijuana plants are NOT a sign of health or potency. In fact, it’s usually just the opposite in most cases.

(There are however numerous high-quality weed strains – like Purple Kush or Grandaddy Purple – that have been generationally bred to produce extremely high THC levels while using anthocyanin instead of chlorophyll).

If all of this makes sense to you and you STILL want to learn how to cultivate pot that looks like something out of a science fiction movie, then without further ado we present to you our simple, step-by-step guide on how to grow purple weed.

How to Grow Purple Weed: The Step-by-Step Process

Before we get into the actual process of how to grow purple cannabis, it’s worth pointing out that there are some strains (like those we just mentioned) that will grow purple all on their own. These plants have been “genetically engineered” to produce anthocyanin rather than chlorophyll, and will grow purple on their own merit – you don’t have to do anything special to them.

How to Grow Purple Weed: The Step-by-Step Process

That said, the following step-by-step process is assuming you are trying to grow purple weed from a “normal green” strain – in other words, how to turn weed purple that would otherwise be green.

Step 1 – Plant the seeds (or root the clones)

The first step in making purple bud is to (quite obviously) plant the seeds. This process is just the same as you would grow any other cannabis strain, and includes properly germinating the seed, managing the vegetative stage, and adjusting the light schedule as you enter the flowering stage.

Related article

Step 2 – Wait until the flowering stage

Once your seedlings have sprouted and your crop has successfully and healthily survived the all-important vegetative state, your process of “converting” from green to purple marijuana will begin to take place once the plants have started showing signs of sexual maturity. In other words, have crossed over from the veg stage into the flowering stage.

Kindman Colorado | Complete Review

Step 3 – Adjust your “Temperature Diff”

Ok, so now that you’ve made it to the final step, are you ready for the all-important secret of how to grow purple marijuana? It’s a bit anti-climatic, but all you have to do is expose your mature plants to large temperature differences between night and day.

In order for your weed plants to turn purple, they need to be exposed to large changes in temperature (roughly 30-degrees Fahrenheit) between night and day.

In other words, if your light exposure temperature (daytime) range is around 80-85 degrees Fahrenheit (27-30 degrees Celsius), your “lights off” (nighttime) temperature range should be around 50 or 55 degrees Fahrenheit (10-13 degrees Celsius).

The drastic exposure to cooler temps will limit the production and activity of chlorophyll, causing the anthocyanin pigments to “take over.” Pretty cool how science works, huh? (This is also why the leaves on trees begin to change colors when exposed to cooler temps in autumn).

One important word of advice however is to not go too radical with your temperature fluctuations. If you expose your weed to temperatures much below 50 degrees Fahrenheit, they’ll probably die off anyway, at which point you’ll have brown weed instead of purple (or green) weed.

If everything goes according to plan (which is a big “if”), you should see the buds start to turn purple around two weeks before harvest. As we noted earlier however, potency really has nothing to do with the color of the bud; for all intents and purposes, purple buds are no more potent than green buds of the same strain.

(Since this article is about how to grow purple weed and not how to grow weed in general, check out this article for detailed tips on how to grow cannabis from start to finish for the absolute beginner).

Other Techniques for Growing Purple Weed

Realistically, there are other “methods” and techniques for growing purple weed other than exposing the plants to colder temperatures. However, these mostly involve nutrient deficiency (i.e. limiting the uptake of important nutrients like nitrogen and phosphorous), which is a pretty silly thing to do to your marijuana if you want to have any semblance of a good, healthy crop.

For example, if you add nutrients manually rather than using an all-in-one super soil, you could hypothetically decrease the phosphorous intake until the buds and leaves start showing hints of purple. Again, though, this is definitely not advised as it would be pretty foolish to decrease the health of your plants just for the sake of getting some “cool” variations in color.

If you really, really want to grow purple weed, then exposing the plants to 30 degree temperature fluctuations really is the best way to go. Whatever you do, just promise us you won’t add purple dye or food coloring to the soil or water. Please, please don’t do that.

Final Thoughts on How to Grow Purple Weed

All in all, growing purple weed is a pretty easy possibility no matter what strain of cannabis you’re cultivating. Realistically, all you’ve got to do is expose the crop to drastic night/day temperature differences, and the plants should start to produce anthocyanin rather than chlorophyll, which reflects violet wavelengths while absorbing everything else (in other words the leaves and buds will appear purple rather than green).

Contrary to what your grower or “expert” budtender might tell you, however, purple weed is NOT any better or more potent than “regular” weed. In fact, it’s usually a sign of inadequate or amateurish growing. If there are strains out there (like Grandaddy Purple) that are more potent than other strains, this is down to genetics and certainly has nothing to do with the fact that the buds are purple rather than green.

As for how to go about exposing your plants to 50-55 degree temperatures, this is actually the tricky part. A portable A/C unit is of course an option, if you’re willing to spend some extra cash on your operation just to get some violet nuggets.

Other options include transferring the plants outdoors at nighttime (if the outdoor temps are colder than your indoor temps) or transferring them to a moderated refrigerator, but those of these present obvious disadvantages that will likely stress your crop, at which point you’ll end up with poor, low-quality weed.

If you do want to learn how to grow purple weed, your best bet is just to find some seeds or genetic clones that will grow purple on their own. Otherwise, you may have a tricky time getting the visually-appealing results that you want.

Related article