Why Is Pheno-Hunting Important for Rosin?

The Press Club Best Cannabis Strains Pheno -Hunting
The Press Club Tips and Tricks Viviane

Viviane Schute       

Cannabis enthusiast and student of the art of solventless extraction


✅ Updated 12/28/20 

The search for an ideal specimen of any given cannabis cultivar, or strain, is known as Pheno-hunting. The term “Pheno-hunting” comes from the word phenotype, which is the set of observable characteristics of an individual plant. These characteristics, such as bud structure, trichome production, terpene content, etc. are the result of the unique interaction between environment and genetics. 

While individual plants of a particular cultivar each carry the same basic genetic code, those genetics express themselves slightly differently from one plant to the next. Pheno-hunting is the process of identifying true champions from the sea of winners (and some losers), and then duplicating those exact champion genetics from one grow to the next.  


Qualities of a Winning Phenotype 

So how do you know when you’ve found a prize phenotype? What qualities are you looking for in a keeper?

Finding the ideal phenotype that dumps copious amounts of durable, resin-packed trichomes during ice water extraction are excellent cultivate for rosin. For both flower rosin and hash rosin, the terpene content of the cannabis plant is crucial as well. 

Trichome heads that easily rupture and leak the resin contained inside generally do not perform well for ice water extraction. If you rub some of the plant's sugar leaves together and the trichomes feel like gritty grains of sand, this is a good indicator that the heads will hold up well for making hash. If they smear apart in a greasy mess, they are not as good. 

Plants that grow with some extra space between bud sites are also better than plants that grow with super-dense buds, with all the bud sites and calyxes packed in together tightly. More airy and spaced-apart flower structure is actually better for washing hash. 

Both the specific kind of terpenes and the concentration of those terpenes produced by the cannabis flowers are important to consider when pheno-hunting. Flowers that smell the strongest will likely be front runners in your pheno-hunts. 

As for plant growth, lots of vigor during vegetation, adaptability  to any temperature variances, strong scent before flowering, resilience to pests/mildew/mold, are things to look for. But remember, we're not trying to get the heaviest yield possible. It's more about the quality of the resin, not the total weight you can pull from the harvest. 

Read more in the articles Cultivating Cannabis Specifically for Resin Production and Breeding To Collect Trichomes




How To Conduct a Pheno-hunt

Pheno-hunting is possible when starting new cannabis plants from seed. Every seed that pops will be either male or female, so the first step is to identify the females and discard the males once they show their sex.

The Press Club Best Cannabis Strains Pheno-Hunting

Once the males are pulled, clone each one of the remaining females. Mark the parent plant and its corresponding clone with the same numbers and/or letters, so that every clone can be linked back with its parent. 

As the females complete their vegetative growth phase and enter the flowering cycle, pay attention to how the plant is thriving in the garden, the size, smell, and structures of the flowers, and the trichome production. 

Note the total length of flowering times for each specimen. Some of the plants may be ready a couple days before others, which is good to take into account when selecting a keeper. When gauging for ripeness, use a jeweler's loupe to inspect the color of the trichome heads. You should see them turn from clear to milky and then amber at the base of the head.

After you harvest and dry the flowers, place them into mason jars for proper curing. Label each jar with the same letters/numbers as the corresponding clones from the parent plant.  


The Press Club Best Cannabis Strains Pheno-Hunting

Last Test: Wash and Press

Whether you’re using fresh frozen material or dried and cured buds, it’s time to test the flowers for bubble hash production. Use an ounce or so of material and conduct a test wash. See how much yield you’re getting and make notes about the corresponding parent plant. Do the trichomes stay intact throughout the ice water extraction process or do they break apart and create an oily mess? How much yield are you getting (as a percentage of the weight of the starting material)? 


If you don't want to do a full hash run using bubble wash bags with an ounce of material, you can do a mason jar test wash. Learn more in How To Test Wash Starting Material Before Washing Bubble Hash.

Also, use some of the dried and cured flowers to press flower rosin, if flower rosin is something you’ll consider extracting. Test the quality and yield from each sample. 

After weeks of assessing the growth of each plant and then seeing how it performs for extraction, it’s time to pick a winner. Locate the clone that corresponds to the best bubble hash and rosin you extracted during testing and this plant becomes your source for all future cuttings of that strain. 

Congratulations, your pheno-hunt is complete!





Pheno-hunting is a numbers game, so the more plants that you can search for the true winner, the better. Like a unique fingerprint, individual plants manifest varying characteristics from the same genetic code. Pheno-hunting is the task of finding the best specimen for hash and rosin production, and then replicating that phenotype by cloning that particular plant.  

Enjoy the hunt!  


What does pheno-hunting mean?
Pheno-hunting is looking for the ideal phenotype, or genetic expression, of a particular cultivar. Pheno-hunting helps you find the plant with the resin production that best suits your needs, and then take cuttings of that plant for replication. 

How do you do a pheno-hunt?
Grow lots of different plants from the same genetic stock and see which one you like the best. Take samples of material from various phenotypes and conduct a test wash, press rosin, etc. 

What is a phenotype?
The set of observable characteristics of a specific plant, or the specific genetic expression of a plant from a certain cultivar. There are different phenotypes for every cultivar. 

What do you do after you select a winning phenotype?
Maintain the selected plant in a vegetative stage of growth, and take cuttings of that plant. Those cuttings will be exact replicas of your chosen phenotype. 

Do all seeds of the same cultivar produce the exact same phenotype?
No, the seeds of a specific cultivar will produce different phenotypes. There will be genetic variations between the plants that are grown from seeds, so pheno-hunting when starting from seeds is important. 

The Press Club Rosin Starter Guide

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