How to create an autoflowering cannabis strain

How to create an autoflowering cannabis strain
Miguel Antonio Ordoñez

The process of breeding autoflowering strains is relatively easy in its theory. However, if you want to cross traits from a non-autoflowering variety of cannabis with an autoflowering strain, things can get a bit more complicated.

Autoflowering cannabis strains have some distinct advantages that make them highly attractive to many growers. These plants are usually compact and often don’t exceed 1 metre in height. This makes them an ideal choice for growers who want to be as stealthy as possible, and those who simply don’t have access to enough space to grow towering plants.

Autoflowering varieties are fast and will flower automatically based on their biological clock instead of photoperiod strains that require a change in the light-dark cycle in order to initiate flowering.

This  creates the possibility to crop multiple harvests per year or season.


As many smokers, growers, and breeders will know, there are two main subspecies of cannabis: Cannabis sativa and Cannabis indica. However, there exists another subspecies known as Cannabis ruderalis.

Ruderalis is a short, shrubby subspecies that is said to have evolved around the colder and darker environments of Siberia. Long summer days and cold winter nights triggered an adaptation in ruderalis that allows it to flower and therefore reproduce without the need for a specific light style. By the end of the day, the plants needed to find a way to survive.

Cannabis ruderalis strains have been bred with indica and sativa strains in order to create autoflowering hybrids that incorporate the autoflowering characteristic, but can provide larger quantities and better quality bud than growing pure ruderalis alone.


So, it’s clear to see that ruderalis genetics are essential to breeding novel autoflowering strains. You could always select an autoflowering strain that exists on the market to begin breeding, or you can create your own if you are looking to harness particular traits. To do so, you will need a good amount of seeds to get your initial plants started.

You are encouraged to obtain regular (non-feminized) autoflowering seeds for breeding purposes. Feminized seeds are sold to growers in order to ensure that only female plants occupy the grow space, eliminating the chances for an invasive male to appear and potentially pollinate nearby females. A large supply of regular seeds, however, will hopefully supply you with a female to male ratio of 1:1.

As your seeds grow into plants and reach the end of the vegetative phase, you will need to pay close attention to the sex of your individual plants. If your main aim is to simply form a large supply of seeds, you can let nature take its course and allow the plants to pollinate themselves.


If you want to start developing your own strain, then more work and dedication is required. Utilizing selective breeding, you can take the plants that display the desired traits and separate them from the others. For example, the plants exhibiting the most potent aromas, speed of growth, or ideal size may be selected.

The chosen plants will then be kept entirely separate from the other plants, and pollination will take place in a controlled environment such as a grow tent or a different room, with great care taken to prevent external, different pollen from entering the breeding space.

The mother and father plant do not need to be the same strain, but if you are planning to continue the line you started with simply use sibling parents and the seeds produced should lead to plants with the desired traits selected. Usually within 3 or 4 generatins the impressive resutls start to show up. It takes time, but its worth it.


The process of breeding autoflowering strains, as stated above, is relatively easy in its theory. However, if you want to cross traits from a non-autoflowering variety of cannabis with an autoflowering strain, things can get a bit more complicated. If you are already selectively breeding autoflowering strains, you can use your own plants to provide the autoflowering traits.

The autoflowering gene is recessive, meaning that both parent strains must posses the gene for it to be passed on. Therefore, this process isn’t as easy as breeding an autoflowering strain with a photoperiod strain and expecting a strain with autoflowering genes to pop out of the other end. Also, autoflowering genetics are known to be unstable, making stability and consistency a potential issue.

To start the process, purchase an autoflowering strain or select one from the crop you have developed. Next, you will need to select a photoperiod strain, be that an indica, sativa, or hybrid variety. The strain you pick will depend on the desired traits you want your future strain to retain.

In most cases none of the offspring from these two plants will posses autoflowering traits. But don’t worry, that is merely part of this more complex process. The offspring will still carry the autoflowering gene and are capable of passing it on to the next generation.

When you breed the seeds of the offspring together, autoflowering plants will come to be. Only 50% of the offspring will have passed on the gene, so only 25% of the next generation will be autoflowering in nature.


Breeding the plants from the third generation should result in a next generation of plants featuring 100% autoflowering genes. Although this seems like the end of the process, and it can be, this is when the fun starts and the genetic potential usually opens up.

You can continue a similar breeding protocol to really bring out the traits of the first photoperiod strain you started the process with. This is known as backcrossing.

To do this, take the best specimens from your new autoflowering crop, and cross these plants with the original photoperiod variety. Then, repeat the above process until the third generation of 100% autoflowering plants is formed, this time with more of the desirable traits from the photoperiod strain.

Miguel Antonio Ordoñez
Miguel Antonio Ordoñez

Miguel Ordoñez is a long-time writer by trade. Utilizing his AB Mass Media and Communications degree, he has 13 years of experience and counting. He’s covered a wide array of topics, with passion lying in combat sports, mental health, and of course, cannabis.