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Cannabis Phenotype: Definition, Examples & Tips to Select Weed Phenotypes

August 27, 2021

Cannabis phenotype only matters for breeders and biologists, right? 

While it might sound like a scientific term irrelevant to those cultivating smokable colas only, learning about it has various benefits for any weed farmer.

For one, it deepens your knowledge about your favorite green plant. 

More importantly, it helps you understand why one cannabis seed batch developed into a gorgeous garden, and the next one shows change you didn’t wish to see.

Strap in. Today, we’re taking you through everything you need to know about marijuana phenotypes, from the very basics to the intricacies and practical aspects of this ganja-growing topic.

Purple Marijuana Leaves

What is cannabis phenotype?

Marijuana plants structurally develop under the influence of two intertwining factors—genetics and environment. 

The genetic composition defines the range of physical possibilities for any living being, including vegetation. The environment is the deciding factor in which of these characteristics emerge as it develops. 

The visible traits of a weed crop make up the cannabis phenotype. It's the expression of its genetics that you see during growth.

In plain language, weed phenotype includes the material characteristics of your plant. Everything from the height and growth rate to shape, color, smell, and resin production falls under this umbrella.

How To Make Cannabis Have Pink Or Purple Buds?
Pink weed buds

What are cannabis phenotypes?

You now recognize how genetics and environmental factors combine to create each iteration of a marijuana plant. Let’s discuss cannabis phenotypes in a bit more detail.

Phenotype variations are observable parts of the evolutionary process of humans, animals, and plants, expressing their genetics under a certain set of outward influences. 

They determine what you can see and how an organism behaves in its environment.

The situation is the same whether you’re dealing with a human or a weed herb. The genome of a particular variety doesn’t have to change, but the growing conditions determine the resulting marijuana phenotype

It influences the following aspects:

  • The shape of the plant and buds.
  • Smell and taste of the colas.
  • Color of the foliage and flowers.
  • Potency through resin production.

The gene pool of any cannabis seed contains plenty of options for physical expression. No matter how similar they look, no two little seeds carry the same genetic information!

We’ll go into the relationship between genetics and the weed phenotype soon. 

For now, remember that the setting triggers certain genes and inhibits the others, determining the observable traits of a crop.

grandaddy purple
Granddaddy Purple

Examples of a weed phenotype

Let’s clarify this weed phenotype talk some more by providing concrete examples

Blue strains are a great example due to their unique coloring. We’ll take the Blueberry cultivar family with its gorgeous blue and purple hues.

Sow a batch of these marijuana seeds in your outdoor garden. You’ll likely end up with streaks of blue and violet on the cannabis leaves, some translating to the buds as well. 

Then, take the seeds from that very same pack and plant them indoors, providing high temperatures in periods of light and darkness. They might develop a light shade of blue or remain green with only hints of purple throughout their development. 

What happened there? A Blueberry weed seed, or a weed seed with a dash of Blueberry in its heritage, carries the genetic information that makes it possible for the crop to produce blue and purple shades on the fan leaves and flowers. 

Still, plants most often display this characteristic when exposed to cooler temperatures. 

By keeping your Blueberry strain in a consistently warm environment, you’ve prevented it from expressing that particular trait. Both green and purple Blueberry cannabis plants are the same variety. They’re simply the different marijuana phenotypes of the cultivar.

Gorilla Glue is another good example, especially since its popularity makes it a pot plantation staple. GG#4 is the favorite among the family, but not the only one. 

Gorilla Glue Autoflower
Gorilla Glue Autoflower

Compare it with its genetic sibling, GG#1, and you’ll see that they look and taste the same but produce very different styles of high. GG#5, for that matter, displays more indica traits, standing out in your GG garden. 

There’s an endless list of these examples to prove a simple point. The main takeaway is straightforward. Identical genetic origin doesn’t always indicate the corresponding appearance, biochemical composition, and behavior.

How is phenotype different from cannabis genotype?

As we discussed in our PotCast, many weed strains fall under the umbrella of certain cannabis families. 

You can trace their genetic lineage to landraces or popular varieties from the ’60s, but they look different from their parentage. Now, that’s what weed phenotype can do for you.

Most marijuana cultivars have two parents, male and female cannabis herbs. The offspring carries a gene combination of its origins. However, not every two plants will display the same gene pool as their proverbial siblings. 

A genotype is the genetic code of a marijuana plant. This set of features isn’t set in stone. It’s only the range of possible genetic makeups a cannabis cultivar can exhibit. 

The environment ultimately determines which of these characteristics show up in the mature marijuana crop.

Math whizzes out there could think about this as an equation. A genotype (G) combines with the environment (E). The resulting interaction (GE) is what determines a phenotype. 

Inherited genetic traitsPhysically observable traits
Result of parentageResult of environment 
Internal code for growthExpression of the internal code

Note: Today, we’re dealing with phenotypes in particular. If you’re interested in learning more about the relationship between genes and their physical expression, check our genotype vs. phenotype report and/or the video below.

Why is phenotype used to describe cannabis strains?

Cannabis comes from the days of yore before we modern humans discovered it and started exploring the potential it has to offer. 

These magical plants grew naturally in different environments. They adapted to their climates and other environmental conditions, developing into different cannabis phenotypes. 

For instance, indica varieties originated on the Afghani mountains and the Asian subcontinent. They grew accustomed to cooler temperatures, weather extremes, and fresh mountain air. 

Their appearance shows those evolutionary changes, with short, stocky, bushy stature and a quick flowering time that allows them to thrive before the first days of winter. 

On the other hand, sativa varieties originate from equatorial jungles. They grow tall and slender and take their time to bloom, making the most of the heat and humidity provided by their surroundings. 

We no longer deal with landrace indica and sativa cannabis that grow only in their original environments, though. Instead, seeds got carried across the oceans, mixed, blended, and modified for different conditions to suit the needs of the ever-expanding cannabis market. 

These new hybrids in the weed world produce various genotypes, leading to an even greater number of cannabis phenotypes. This diversity allows you to get picky, smoking only pot with the flavor and effect profiles you prefer. 

Understanding how each genetic profile can translate into phenotype brings heterogeneity. The scope of available options expands for growers, stoners, eager breeders, and everybody in-between. 

Hybrid Weed
Hybrid cannabis plants are the most common type now

Environmental factors that affect weed phenotypes

We’ve hammered on the importance of environmental factors on different phenotypes of weed enough. It’s time to discuss which environmental factors play the most significant role in developing seeds into harvest-ready crops.

Remember, while there’s some variance from one seed to the next, they’re not wildcards. A specific set of traits stems from one genotype. It’s on you to provide the environment necessary for those traits to shine through.

Let’s divide these characteristics into two categories:

  1. Affected by one particular environmental condition.
  2. Affected by the combination of multiple environmental influences. 

The former includes characteristics, such as purple coloration, only resulting from exposure to cooler temperatures. These cannabis phenotype aspects are more limited than the latter category and easier to reshape through your actions. 

More frequently, different marijuana phenotypes occur as the result of various factors working in unison. These conditions include:

  • Temperature and humidity.
  • Lights and light spectrums.
  • Growth mediums.
  • Trimming, topping, and pruning.
  • High-stress and low-stress training.
  • Nutrients and fertilizers.
plants in greenhouse
Temperature, humidity & other factors may affect cannabis phenotypes

Switching up any of these cultivation aspects leads to differences in cannabis phenotype. They can alter the aroma, cannabinoid and trichome production, foliage density, and the size and potency of your colas. 

These aspects are more challenging to control. Still, providing the optimal conditions for each strain allows it to reach its highest genetic potential.

The development of marijuana phenotypes 

Marijuana phenotypes start developing early, sometimes even before the weed seed gets germinated. 

External conditions affect certain traits of a sprout, from node length and density to the size of those first little flowers. 

Ever since that point, the environment fosters certain traits while inhibiting the rest, guiding cannabis into the direction of a certain physical expression.

Apart from the environment, cannabis phenotypes might develop due to a recessive trait. These characteristics get shaded by dominant ones and don’t show in the parent plant. 

For instance, a crop could have a gene for leaf density that it doesn’t display in the weed phenotype. It still transfers it to its children. In that case, you end up with an appearance different from what you’d expect looking at its parentage. 

8 tips for selecting the best weed phenotype

Commercial growers and those looking to take cuttings from first-rate marijuana herbs benefit from knowing how to determine the most desirable weed phenotype. 

These eight tips help you pick the best from the bunch and extend your garden on the highest-quality possible basis.

1. Use clones for homogeneity

Using clones ensures maximum consistency and efficiency in choosing the top cannabis phenotype. 

It’s not the most fun, experimental approach, but it guarantees the exact genetic copy of an already successful mother plant. 

You get a batch of the same, already optimized marijuana crop (as long as you keep the environment consistent as well).

2. Germinate liberally

If you prefer to keep things fresh and grow your weed from seed, skip the clones. Instead, detect the best phenotype by watching your seeds develop into marijuana plants. 

Cannabis plant in veg state

If you’re planning to grow, say, five crops, buy cannabis seeds in a 10-pack. Germinate all of them and observe their characteristics throughout the various growth stages. Think of the following: 

  • What characteristics do you want? More indica-style or closer to a pure sativa?
  • Are you going for a strong aroma, or are you fine with more discreet scents?
  • Are you growing for maximum potency or prefer medium power in plants? 

Find the herbs with characteristics that match your desires and preferences and nourish them till harvest. Discard the ones that don’t fit your ideal cannabis phenotype. 

3. Consider your preferences

The ‘best cannabis phenotype’ category isn’t one-size-fits-all. It differs from grower to grower, stoner to stoner. Recognizing this individuality is the way to find the best option for you. 

Think about different phenotypic characteristics you wish to see in your homegrown cannabis. For instance:

  • The aroma. Before you pick a type of ganja, give it a good sniff. Sweet cultivars are the go-to for some tokers, while others prefer a stinkier strain. Remember that the aroma mirrors the terpene profile, which has other implications.
  • The effects. Cannabis strains have different effect sets. In general, indica is more sedative, while sativa is energizing and uplifting. Consider the chemical composition responsible for the effects, which also changes with cannabis phenotype.
  • Bud and yield size. Some weed phenotypes produce large, airy colas. Others bear chunky, dense, nugget-size buds. Knowing this, in combination with the expected yield size, lets you optimize for space. 
  • Growth rate. The flowering period tells you how many growing seasons fit in a calendar year. It affects the amount of bud you’ll be storing when it’s all done and dusted. 
Nate Hammer With Bud

4. Purchase from reliable sources

Renowned seed banks earn their reputation by providing consistent, reliable products of good genetics

They ensure that their seeds provide consistent results and grow into the plants as advertised. There are also zero duds in your seed pack.

Of course, you can’t expect each seed to be a mirror image of every other one

Still, as long as you’re purchasing from a source known for product quality, the best phenotype of weed is pretty much a guarantee.

5. Rely on breeding experience

Related to the previous point, your best source of weed seeds is one with a lot of breeding under its belt. Research competence and the track record of a seed bank. At least a decade of experience is ideal. 

Time in business shows that their experts are already well-versed in singling out the best genetic traits. It warrants a set of similar plants from a genetic source. 

A well-bred strain reduces the possibility for variance. As such, it reduces the risk of something going awry. 

6. Choose feminized

Choosing the best marijuana phenotype is essential if you’re creating new strains or cannabis clones. You get a bonus as a grower for smoking purposes. 

Having as little variance as possible is a good thing in your case, and going feminized ticks two boxes in one stroke.

Feminized seeds have phenotypes, but they display less variance than those carrying male and female cannabis. Fem crops usually have only one parent. 

There’s much less room for dormant genes to go against your gardening plans and expectations. 

Marijuana outdoors in flower
Feminized plants in early flower stage outdoors

7. Consider hybrids

Indica and sativa cannabis are two sides of the genetic spectrum, but they’re not the only options. There’s a whole scope of in-between possibilities, letting you enjoy the best of indica and sativa traits.

Of course, a blend of opposing genetics sometimes leads to a surprise in your garden, but previous tips come to the rescue

Pick a good source of stable seeds for a quality cannabis phenotype tailored to your needs.  

8. Optimize to maximize

Finally, let’s go back to the environment argument. Growing conditions are essential in determining what characteristics a certain genotype displays.

Maximize your chances of achieving the ideal marijuana phenotype by picking quality cannabis seeds with good backing and optimizing the growing situation to trigger the traits you wish to see. 

Master the basics of weed farming and get familiar with the needs of your particular strain. Follow these as closely as possible and avoid rookie errors to help the environment push the genes in the right direction.


Before we leave you to your garden, let’s answer the questions about cannabis phenotypes we often hear in the community.

Is sativa a phenotype?

Yes. In simple terms, sativa is a phenotype of weed.

The distinction between indica and sativa refers to different general phenotypes of the cannabis genus. In the case of a sativa phenotype, the plant displays the following physical traits:

  • Tall stature.
  • Elongated leaves.
  • Large, airy buds.
How Are Sativa Plants Different From Indica?
Sativa dominant plant in early flowering stage

Do feminized seeds have phenotypes?

Yes, they do. Feminized cannabis seeds differ from their regular counterparts only in the fact they have 100% female genetics. 

Breeders germinate many seeds to locate the best phenotype and then feminize. Fem seeds come from different strains, though, which leads to phenotypic variation.

Is every seed a different cannabis phenotype?

No, or at least not in most cases. 

Cannabis seeds of the same strain generally display the same physical characteristics when grown in the same environment. The differences are slight and far from enough to call each seed a different marijuana phenotype.

How do you get a purple phenotype cannabis?

Exposing your crops to colder temperatures brings out a purple hue, but only if they have the genetic predisposition for such coloring. 

If you want purple weed, you’ll have to pick a strain from the purple family. Then, drop the temperatures during the hours of darkness, and you’ll get a purple marijuana phenotype.

Is growth rate a component of cannabis phenotype? 

Yes. Different phenotypes display different appearances and behavior.

The growth rate is one of them and among the initial expressions of the weed phenotype. 

Breeders often cross strains to get seeds with accelerated growth rates without compromising the harvest potential.

What is pheno finding?

Pheno finding is the process of selecting the best plant from a batch of similar phenotypes

Breeders observe a garden of cannabis plants and look for the most desirable traits. 

Once they locate them, they use those crops for clones and cuttings. Others get discarded (we wouldn’t waste smokable weed, though).

Are clones better than seeds for cannabis phenotype consistency?

Yes, but it takes some fun out of it. Seeds inevitably introduce some variation into the mix since not one has the carbon copy of the others’ genetic makeup.

Cloning copies genes of one plant, letting you maintain an entire setup of identical weed phenotype twins.

Indoor Marijuana

Final points about marijuana phenotype

Now that you have a much deeper comprehension of cannabis phenotypes, you’ve gained several important advantages for your next cultivation journey. 

For one, you’ll know how to find the cannabis strains that suit your needs, desires, and growing conditions. 

Once you have that down, you’ll be more aware of the factors necessary to achieve these optimal features. 

Finally, you won’t start doubting your seed bank or growing expertise if a seed batch turns into a garden that looks nothing like the info you found online.

Stay tuned to our blog for more guides such as this weed phenotype breakdown

We deal with everything from growing practices to the science behind our favorite flowers, helping every community member achieve a lovely, thriving garden. 

About the Author: Kyle Kushman

Kyle Kushman is a legend in the cannabis community. He is the modern-day polymath of pot: cultivator, breeder, activist, writer, and educator. After winning no less than 13 Cannabis Cups, there’s nothing this guy doesn’t know about indoor growing - he’s been there, done it, and is still doing it to this day!

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