How to Breed New Cannabis Strains

Do you ever wonder about the origins of your preferred hybrid, indica, or sativa cannabis strains? Skilled breeders are constantly on the lookout for ideal phenotypes within their cultivars, which they can cross with other plants in their strain collection to produce the next batch of sought-after strains. - Written by Randy Villarba

Have you ever wanted to know how some of your favorite hybrid, indica or sativa strains came to be? The search for the right genetics that yield high terpenes and levels of THC is always ongoing for those who grow. Master breeders are always hunting for the right phenotype within the cultivar to cross with other plants within their strain library in order to create the next generation of popular strains.

This is done by finding a strong and potent female cannabis plant and crossing it with a male plant. Ever since the first landrace cannabis sativa and indica strains made it to the hands of cultivators, these genetics have been fused and evolved into the numerous hybrid strains that make up most of the recreational market today.

Sexing Your Cannabis Plants

Cannabis is a dioecious plant, having male and female organs. Identifying the sex of your cannabis plants is extremely important at an early stage based on the characteristics of their growth or the unique shape of their flowers.

When a plant starts to mature, it’s time for a cannabis plant gender reveal. Locate the nodes of the plant, where the leaf petioles and stem connect. The first flower that starts to grow there will be easy to decipher if your plant is a male or a female.

In an indoor garden, you can also identify your plant’s sex by inducing an early flowering stage. While you can flower your whole plant early, keep in mind the process will take roughly 10 days to transition to flowering. If you wish to revegetate your plant, it would take another 10 days after that to reverse the growth process.

Good practice is taking clones from your parent plants you wish to sex, and then flowering those cuttings once they are rooted and mature. This process allows your whole plant to still grow on a healthier, more traditional cycle without putting it through the stresses of early flowering and re-vegging.

Once your male and female plants are identified, separate them as soon as possible. Maturing males and females should be kept in separate gardens. It is also extremely important to be cognizant of moving between male and female gardens, as pollen is extremely easy to transfer. You do not want to cross-contaminate your flowering garden, and potentially degrade your entire crop.

How To Collect Cannabis Pollen

Once you have chosen the right male plant as your stud, the next step is to collect its pollen. You take a paper sheet or plastic container and lay it under a branch with mature and open male flowers. Gently shake the branch and allow the pollen to fall from the flower and collect on the sheet or container. Selecting a black container or sheet will make it easier to see the pollen you have collected.

When working in an indoor environment, isolating your male plants away from your female plants is very important. Pollen can spread easily through open vents and windows. Pollen can also hitch a ride on your body, hair and clothes. If you do not want to fertilize your entire garden, it is good practice to shower and change clothes when switching between gardens.

How To Collect Cannabis Pollen

Pollination of Female Flower

Once you have identified the male and female cultivars you wish to breed, the next step is pollinating the female plant with the male pollen. The best window to pollinate a female cannabis plant is about 2-3 weeks into the flowering stage. Take the pollen you collected from the male plant and gently blow the pollen onto the female plant you intend to hybridize. It typically takes six weeks after pollination for seeds to mature.

Pollination of Female Flower

Deactivating Cannabis Pollen

It is a good practice to deactivate any leftover pollen three hours after fertilization of your female plants. This can be done simply by spraying your freshly fertilized plants with water. Allow your cannabis plants to continue the flowering period.

Seeds will start to emerge and are fully mature after two to six weeks. It is ok to let the seeds stay in the flower during the curing process. It can take about a month before your seeds are ready to be germinated.

Stabilizing a Cultivar

Stabilization through selective breeding can occur naturally over time, harvest after harvest. In order to focus and control breeding, breeders typically start this process through hybridization and backcrossing their genetics.

When you are breeding true, your genetics are stabilized and every seed and plant you pop gives you the same results. Cannabis phenotypes have different genes and are therefore heterozygous. In order to stabilize a cannabis cultivar to always produce the same plant, a breeder would need to get the strain to be homozygous.

Stabilizing a Cultivar


All information, including but not limited to, text, graphics, images and other materials contained on this site are for informational purposes only. No text, graphics, images or other materials on this site are intended to be professional medical advice or a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of your physician or other qualified health care provider with any questions you may have regarding a medical condition or treatment and before undertaking a new health care regimen, and never disregard professional medical advice or delay in seeking professional medical advice because of something you have viewed on this site.