Any cannabis cultivator, from a seasoned professional to a first timer, dreams of growing the best plants they can get their hands on. Whether they are looking for the ideal composition of cannabinoids and terpenes to treat medical symptoms, the healthiest and bulkiest plants they can find to maximize their yield, or something else altogether, they will need to hunt out the optimal cannabis phenotypes to bring their goals to fruition.
This is the portion of cannabis cultivation known as the “pheno hunt.” The pheno hunt can be the best part of growing cannabis, or an obnoxious and expensive task depending on who you ask. Regardless of a grower’s outlook on the process however, it is a critical step in growing the best possible cannabis.
What is a Phenotype?
All living organisms have both a genotype, and a phenotype. In biology, a genotype is the genetic code within the organism that lays out the blueprint for that organism to live. If the genotype is the “blueprint” of the organism, then the phenotype would be considered the “structure.” Proteins are translated from the genotype and come together to form the actual living organism, which is then described as the phenotype.
In the case of cannabis, the genotype will contain code for the expressed phenotype the cultivator is hoping to obtain. For example, a cannabis embryo may contain multiple copies of the genes responsible for purple pigmentation. That genotype is then expressed in the phenotype when multiple copies of the proteins responsible for producing anthocyanin pigments are translated from the plant’s DNA and anthocyanins build up leading to a deep purple cola at harvest. While the genotype is more or less hard-programmed into the organism through breeding and random mutation events, a phenotype can be slightly manipulated through cultivation practices. One more common example of this is utilizing lower temperatures at the end of harvest to stimulate anthocyanin production. While a plant may be genotypically less favored for purping out, the cultivator can push the pheno to its maximum potential with outside influences like chilling to maximize the outcome from a less favorable genotype.
Now with an understanding of what a genotype and phenotype are, we can discuss what it means to carry out a pheno hunt. Depending on the growers’ goals, this could mean a few different things, but in general unless you are a breeder the first step of your pheno hunt will be to remove male plants. Because most cultivators are looking to produce sinsemilla - cannabis with no seeds - removing the main source of pollen from the grow is absolutely critical. Historically this was done by growing plants to a certain maturity in the veg stage until pre-flowers were visible to the grower. From there, male plants can be identified and culled, but this process is both time consuming and prone to error. Once male plants are removed from the grow, the plants can then be pushed into their flowering phase after vegetative clones are taken to generate potential mother plants.
At this point we have carried out our first step of “the hunt,” leaving us with only female phenotypes. The next portion of the pheno hunt is then carried out by growing the plants through a full flowering cycle and observing how they handle the grow and what the final product looks like. This is the portion of the pheno hunt that is a bit more subjective and variable. Growers will evaluate things like terpene and cannabinoid compositions, growth habit of the plant, total flowering time, disease resistance, and final yield. An outdoor grower or a grower with difficulty controlling their environment might pick phenos that have the strongest resistance to molding, while someone who dreams of pressing purple rosin might pick the strains with the highest anthocyanin content.
If you have the time and resources for it, the pheno hunt can be the most fun aspect of growing. Every pack of seeds can be a gamble, and sometimes you win big with a phenotype that expresses exactly what you’re looking for. If you don’t have the resources to carry out the pheno hunt, or you’re not a big fan of surprises, an easy alternative to pheno hunting is to obtain clones of the exact pheno you are looking for. This comes with its own host of risks though, with pathogens like hop latent viroid and certain strains of powdery mildew spreading undetected from grow to grow as phenos are passed from cultivator to cultivator.
Tools that can help
Luckily for growers there are modern tools that can help reduce the risk and strain of the pheno hunt. For a pheno hunter starting from seed, screens like male gene detection can save tons of time and money otherwise spent on growing out plants you will have to eventually kill. For those who obtain phenos through clones, pathogen screens like hop latent viroid and powdery mildew detection can help protect your existing plants from the risk of pathogens carried in through new clone stock. Partnering with a lab that can carry out these screens can mean the difference between a quick and easy pheno hunt where you pick your grow’s “winners” or a long and strenuous slog where a male pheno accidentially slipped through undetected and caused your whole grow to go to seed.