Grow Guide: The Pheno Hunt


Pheno-hunting and selective cannabis breeding are essential techniques growers use to ensure that cream of the crop genetics are passed along to future generations.

There are thousands of strains of cannabis, but to blow your mind even further, every single one of those strains has hundreds of unique phenotype expressions. Pheno hunting is the process of narrowing down that wide selection to find specific plants that express the dominant traits the grower wants to develop. In this Grow Guide, we’re going to be exploring pheno-hunting and sharing some techniques that growers and breeders use to find their winning strains.


When you germinate 100 seeds of a single strain, lets say a newer strain like Gorilla Glue, you will notice that not all of the seeds are the same. Just like parents might have one child who’s tall, one who’s short, one who is blonde, freckled, etc., plant genetics will also be different and unique combinations of their two parents. So those 100 seeds of Gorilla Glue will all grow up to be a unique expression of its parents Chocolate Diesel and Sour Diesel — some leaning toward mom Chocolate while others will express traits from their Sour dad. As growers, it is our job to find the best pheno to cultivate for ourselves and our patients.

seeds_1744-2If you get your hands on seeds from an older classic strain like White Widow you will notice far less diversity in phenotypes — every seed will be almost identical. This is because all of the classic strains have been stabilized through backcrossing and breeding techniques to guarantee uniformity. (Unlike in mammals, inbreeding creates stability in plant genetics.)

But with the ease of access to genetics these days, once a genetic cross happens breeders rarely invest the years of time needed to stabilize the genetics. So buying a pack of seeds doesn’t mean you will get 10 exact Cookie strains, it means you just began a genetic treasure hunt with varying expressions. This brings us to our Grow Guide on how to pheno-hunt through those amazing new-age genetics to find lasting, winning strains.

This Grow Guide can be useful for growers experimenting with breeding or simply growers looking for the newest unique strains.

It All Starts from a Seed

Whether you start with seeds that you created or you purchased a pack of seeds from a breeder or seed company — here you are with a handful of potential.

For ease of this example, we’re going to pretend that you only have one strain you’re interested in hunting through.

During a pheno hunt, organization is key. In order to distinguish a single seed from the pack, we need to give them all unique identifiers. The best method for naming during a pheno hunt is to go back to our ABC’s and 123’s. Let’s say you have 100 Gelato seeds, while planting those seeds give each one a name. At TKO Reserve, we stick with the strain name initial and count upward — G1, G2, G3, G4, etc. Now when you begin to analyze structure and growth patterns, each seed has a name you can refer to. And on that note, beginning a pheno hunt journal to log appealing and unappealing attributes of each offspring is highly recommended.


Battle of the Sexes

As your babies continue to grow, note which ones grow most vigorously — the overzealous seedlings tend to be the males.

Even though this is just the vegetative stage, it’s important to take notes of your favorite plant structures, how quickly they absorb nutrients, speed of growth, leaf structure, etc.

As the seedlings continue to grow, the males will need to be separated from the females. About *4-6 weeks into their vegetative cycle (or 1-2 weeks into flower if it’s a late pollinating male), you’ll begin to notice ‘pre-flowers.’ These gender-identifiers will show up right in the crevice where a branch shoots out from the main stalk. For females, you will see a tiny, pointed sac with little white hairs. For males, you will see a small, round, green globe. Checking for the pre-flowers will help you separate males and females before the plants flip into their flower cycle.


Tech Tip: New genetic technologies allow growers to determine the gender of their plants without having to wait. Steep Hill’s GenKit allows sex determination at a very early stage in the plant’s development, shortening the process from several weeks to several days.

If you are not pheno-hunting for male plants, you can destroy the males (and use the leaves for juicing!)

If you are looking for that special male, you can set them aside to flower in a separate room. Remember to take clones off of all your plants before flower to preserve the genetics.

Flower Time

So now that you’ve weeded out the males, it’s time to focus on the ladies. When they’ve reached the height and size you’re looking for, switch your grow lights to 12 hours of light per day to initiate the flower cycle.

The flower cycle is the time when you will need to pay close attention to how all the flowers mature — this is the time to take notes!

During flower, you’ll want to focus on the following categories: growth structure, hardiness, smell profile, appearance, trichome density and time to peak maturity.

cannaobscura-durbanpoisonGrowth Structure — How does the plant grow? Is it short and stocky or long and lanky? Which plants are growing quickest? When transplanting, which plants have the strongest roots? How many days does each flower take to mature? How many lbs per square foot per strain?

Hardiness — How do the plants react to high heat and low temperatures? How many days can they go without watering? Are they seemingly resistant to mold and pests? Are the stalks and branches strong and thick or thin and weak?

Terpene Profile and Visual Appearance — What aromas are coming off of each flower? Try to identify specific terpenes and write them down. What color are the buds? Is there any color to the pistils? What structures are the flowers exuding?  

Trichomes — Analyze the trichomes using a scope. Are they short-stalked with fat heads or lanky stalks with small heads. If you’re searching for the next best hash strain, these little details make all the difference. Some people will search for strains specifically for their “hashability.”

Peak Maturity — Due to the varying phenotypes in many new-age seed packs, there will be plants that are ready for harvest sooner than others. It can be advantageous to have a plant that can finish early, whether it’s because you want to flip your room faster or you’re growing outdoors and need to harvest before the rain hits.

Finally, Taste Testing!

And now for the best part, reaping the rewards of all your hard work! During harvest, it may be helpful to record the wet weight of each plant to later compare with the dry weight to see how much moisture was lost per pheno.

Analyze the terpenes during harvest, does it smell delicious right away or does the smell need time to mature?

While drying and curing, note which phenos you’re drawn to, how quickly each pheno dries, and the time needed to cure adequately.

After all the necessary post-harvest tasks, it’s finally time to smoke your selections! I would definitely recommend seeking help from employees and friends to taste test the samples. Everyone has a varying palette, so it’s helpful to get feedback from people with different tastes. At TKO Reserve, we type up a template to pass out with the samples that prompts some basic questions to think about while smoking each pheno.


Things to consider while testing each pheno:

Flavor — Does it taste earthy, fruity, skunky, diesely? Does it hit your tastebuds on the inhale or more on the exhale? Does the flavor change from inhale to exhale? Is the flavor harsh on your throat at all?

SmellWhere do you feel the smell — low or high in the sinuses? Is the smell spicy, sharp, floral, fresh, woody, citrusy, or earthy? Is the smell enticing?

Appearance — What colors do you see? What kind of bud structure? How dense are the flowers? What do you see when you crack open the bud? How is the trichome density?

Effect — Does it hit you immediately or slowly? Is the effect brief or long-lasting? It is a mild or intense effect? Is it mentally stimulating? Does it energize you or relax you? Where do you feel the effects most?

After analyzing and tasting all of the phenos, it’s time to make the hard decision to edit down and pick the favorites. If you’re pheno hunting for a certain trait, whether its color, taste, or a specific smell, you can narrow down the crowd a little easier through examining the notes and feedback you receive.

Some growers like to grow all of the phenos more than once before culling out the losing phenos, but typically one run is adequate. Once you’ve picked the one or two winners from this batch of pheno hunting, go back to those clones you took during veg and toss the ones that didn’t make the cut. And while it’s always a little heartbreaking to kill plants, you can be stoked because you made it out of the pheno hunt with a winner!!


Now that you have your winner from that specific strain, if she’s perfect you can continue to grow and dial her in over time. If you’re still looking for a little something extra, you can experiment with some breeding — check out our Grow Guide on Breeding Cannabis for more information.

If you’re like us over here at TKO, you probably have another pack of seeds waiting for you to hunt through so it’s time to rinse and repeat!

Hopefully this guide helps you through the overwhelming task of pheno hunting and opens your eyes to how rewarding it is to unlock new and unique flavor profiles!

Want to learn more? Check out these Grow Guides for more gardening tips and tricks!

Grow Guide: How to Make Your Own Organic Cloning Gel

Grow Guide: Welcome to the World of Veganics

Grow Guide: Cover Crops

About Author

Allie is a NW-based content curator for and an organic farmer at TKO Reserve. She has been a professional in the marijuana industry since she was 18 years old, spending the first five years of her career working for Dope Magazine as lead photographer. Allie has worked on mainstream projects such as Idiot's Guide: Growing Marijuana, Branding Bud: The Consumerization of Cannabis and her own self-published book, As The Grass Grows.

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