The Basics of Breeding Your Own Cannabis Strains

By Luis Cordova
Published: February 24, 2020 | Last updated: December 7, 2021 11:55:49
Key Takeaways

Breeding cannabis is rooted in time, practice, and patience. Luis Cordova goes over the basics of phenotypes, backcrossing, pollination, and seed care to help you create your own marijuana strain.

Breeding Cannabis

Growing your own cannabis is one of the most rewarding experiences for a consumer. However, breeding your own strain is immensely more rewarding. The experience allows you to be creative, in control of your cannabis, and receive feedback about your strain while learning new skills.


Breeding cannabis can be as simple or complicated as the breeder wants it to be. Depending how much time one has for breeding cannabis, the new strain can be entirely different from what’s currently on the market. In this article I will cover the basics of crossbreeding, backcrossing, phenotypes, and other breeding techniques.

Cannabis Phenotypes

Hybrid strains available at your local dispensary have probably gone through a series of trait selection and are bred for many generations. This is usually done to breed for genetic strength and consistency across lineage. Each cannabis seed created in the breeding process will have different attributes from its parents. The variation or difference expressed is known as a phenotype. If you’ve grown cannabis from seed before, you may have noticed that out of 10 seeds, all may grow or smell slightly different; this is an example of phenotype. Because of this, many breeders will go hunting for the specific phenotype of the strain they have purchased. Doing so allows the breeder to have an almost exact copy of the original strain.


When breeding cannabis, you typically want to produce seeds with the same sets of genes (referred to as being homozygous). Having the same set of genes in the seeds will ensure each plant is consistently similar to others and reduces the amount of time to hunt for phenotypes. This will build confidence in buyers of your seeds or product as it remains the same all the time.

After a strain is crossed, many breeders go through a selection process for the best phenotype. To maintain a cannabis strain, breeders will discard any phenotype that’s not similar to the original strain. So, it’s important during your strain selection process that you have a set of well-defined goals for your new strain. This allows you to fine tune your cannabis strain into the best it can be.

Male Cannabis flowers and pollenMale Cannabis flowers and pollen. Source: KLYONA/Shutterstock



With any plant it is relatively easy and fun to go forward with genes to create new strains. Most breeders go through a process known as backcrossing. Backcrossing is essentially the process of cross pollinating the new strain with itself or its original parent. This creates a homozygous in-bred strain, strengthens the genetics, and stabilizes the phenotypic traits. Backcrossing allows for desirable genes to get passed down throughout the generations with very little differences, allowing a breeder to store genetics for long periods, while also being able to work on other strains.

Selecting Cannabis Strains for Breeding

To begin the cannabis breeding process, oftentimes the first step is strain selection. Depending on the desirable traits you want to achieve, this can be a quick process or a very long one. Selection can be as easy as choosing two strains you like. It can also be more complicated through focusing on particular factors. These factors include your grow space, growing media, fertilizer selections, environmental conditions, amount of investment, availability of time, plant characteristics, and popularity of the strain. When purchasing your strains, it is advised to select at least one that is sold as regular seeds.


Most strains are hybrids with plenty of landrace genetics becoming more widely available. Selecting hybrids often means you have less selection constraints or factors to breed for as someone else has done this already. Growing landrace cannabis strains means almost no extensive selection process has occurred. This will allow you to select the phenotypes you like and develop them further. They can also be crossed with other hybrids to develop new strains.

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Getting Started Breeding Cannabis

To begin breeding cannabis, you may already have many of the tools and skills needed. The area you will grow in must first be selected — indoors or outdoors will help you decide what extra equipment you may need. No matter the area you choose, an additional closed location will be needed to house pollen-producing males.

Additional tools required include a desiccant material such as silica gel, multiple size Ziploc bags, fine synthetic paint brushes, at least a 60x jewelers loupe, and space in the refrigerator or freezer. You could also use a vacuum sealer, aluminum foil, food storage bags, or anything to reduce moisture when storing pollen and seeds.

Male plants do not flower, however, those that produce large amounts of pollen will pass on higher yielding buds to their female progeny. Male plants do not flower, however, those that produce large amounts of pollen will pass on higher yielding buds to their female progeny. Source: Yarygin/Shutterstock

Cannabis Breeding Basics

In order to cross the strains, two groups will have to be developed. One group will be females with the desired traits and the second group will be males. Selection of male plants can be more difficult as they don’t produce female buds and make the final product unknown. Typically, male plants are chosen based on their smell, appearance, and pollen production. Generally, male plants that produce large amounts of pollen will pass on higher yielding buds to their female progeny.

The male plants will need to be isolated from all other females to reduce cross pollination of unwanted males. When working in the male room it is imperative not to go into the female room until you have changed your clothing and scrubbed all exposed body parts. If possible, it is advisable to avoid the female room for at least 12-24 hours. Male pollen can be collected in a bag, labeled, then placed into a bigger labeled bag that includes a small amount of desiccant, and placed in a cool environment like a refrigerator. If available, a freezer with a temperature of 39°F is ideal to increase its shelf life.

Once the female has been selected, it is pollinated. Pollination is usually done during the second or third week of flower for most indica species. Sativa species can be pollinated a little later as their flowers take longer to develop. Pollinating within this timeframe allows for the seeds to set and mature. To pollinate, stored pollen is removed from storage and allowed to warm up to room temperature. The fine paint brush is dipped in the pollen and then spread all over the female flowers. Other pollination techniques entail taking a bag of pollen and placing it in a big plastic bag. The flower is placed in the first bag and both bags are shut. The flower is then shaken and the bags are tied. The pollen can settle for a bit and the bags are removed. After pollination, the female buds will begin developing seeds that are a recombination of the parents’ genetics.

Seeds are mature when they develop a uniform brown color with dark speckles or black stripes.Seeds are mature when they develop a uniform brown color with dark speckles or black stripes. Source: Roxana Gonzalez/Shutterstock

Seeds can be harvested when they begin to have a uniform brown color with speckled or black stripes. Often the outer coating of the seeds will turn brown, showing they have matured. However, if the outer coating is still green it doesn’t mean the seed is immature.

During the seed maturing cycle it is important to carefully check your seeds as they may fall out of their coating and be lost when they are fully mature. Seeds should be placed inside a labeled bag. This bag is then placed inside a bigger bag that has desiccant material in it. Typically, you want two grams of desiccant per two grams of seeds. This ensures no moisture enters the bags.

Alternatively, the same system can be used with any container available. The seeds can be stored in a refrigerator or freezer for up to two years. It’s important to check the desiccant material at least every three to six months as it will absorb moisture and reach a point where they can no longer absorb more. If stored properly some seeds can last in storage for up to five years.

After your seeds are collected, the process of growing and selecting phenotypes can begin again. This process can occur for as long as you want till you achieve the traits you desire. Additionally, you can also change the direction of the strain and give it an entire new set of traits.


Creating a truly great strain may takes months and years of continued selection and stabilization to get the best phenotype. Breeding is rooted in time, practice, and patience. It’s important to remember your goals and be happy with what you are doing. So, if you’re just growing to grow cannabis, consider jumping into the world of breeding. The more breeds that become seeds can produce something completely new for the next generation.


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Written by Luis Cordova | Plant Biotechnician, Pharmaceutical Scientist

Profile Picture of Luis Cordova

Luis holds a M.S. in Plant biotechnology and Pharmaceutical Science. He is a long-time cannabis grower He has put his focus on breeding cannabis and development of organic soils for tropical regions. He loves how much the industry has grown and changed. He hopes to pass on new and old knowledge to all growers across the world.

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