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best way to breed a stable cannabis seed

Breeding cannabis requires quite a lot of space. You need a nursery and propagation area and different rooms for male and female specimens to avoid unwanted cross-pollination. Even more space is needed if you intend to start breeding polyhybrids over multiple generations starting with four inbred cultivars. If you intend to begin this process, you’ll need to learn how to pollinate your flowers in the correct way.

This consistency is possible, and can be achieved by stabilising the genetics of a strain. This will then produce seeds that are more homozygous, featuring significantly less variability between phenotypes. But how can breeders go about stabilising a strain?


Seeing as you’re considering breeding, you are probably already well aware of this fact, but it’s always worth reiterating: Keep your males away from your females! This is especially important when looking to breed a polyhybrid because of the increased chances of breeding the wrong varieties together.

Differences in phenotypes can manifest as variability in size, resin production, colour, and so on. Strains can also vary in their chemotype. This refers to the chemical constituents that they manufacture. One plant might have higher levels of a specific terpene, whereas another may have slightly higher levels of CBD. If you germinated a bag of seeds that all shared the same lineage and noticed a large difference between the phenotype of each plant, this would mean that the strain is unstable, and that the seeds are heterozygous. Although this isn’t necessarily an issue for hobby growers, it can become problematic for commercial growers looking for strict consistency among their crop.

Time in the grow op will have already given you a keen eye for pheno hunting. Plus you have developed the hands on cannabis tradecraft skill set to succeed.

The vicissitudes of plant genetics can be seen when driving past any modern food crop. Fields of heavily hybridized and inbred cereal crops, for example, will generally be homogeneous. However, there will always be some freaks that stand out from the crowd.

The solution is to introduce a novel father into the gene pool to strengthen the strain by increasing genetic diversity. Within a few generations, the depression will be relieved and plants will regain their genetic vigor.

It is quite possible to produce only unwanted phenotypes in a complete grow. It is also possible that great-looking new phenos contain undesirable traits in the next generation.


Without genetic assays that can give precise information about the plant’s characteristics, experience plays a big part. Growers rely on look, growth pattern, leaf shape, color, and potency for desired new strains. They select a number of plants for breeding from the same seed batch that have similar characteristics. These plants are interbred, and the plants that resemble the desired strain are bred together again.

Stabilizing your indoor crop at home can be a little more difficult because of a number of factors. Limited numbers of plants means limited seed production. This usually means that the few seeds produced do not represent the complete new genetic diversification.

If you are keen to breed your own strains of cannabis, then you are going to need to know how to stabilize the seed stock. Stabilizing a strain means it becomes homogeneous, and any seed from that strain will breed true. Classically, landraces are stable. A seed from one plant will grow the same way as another seed from another plant from the same crop.

Outbreeding can solve these regressive attributes. When the breeding population is small, inbreeding depression can occur more rapidly. This is often a problem in Schedule 1 countries. The law means there simply isn’t the space to generate enough interbreeding stock to select prime examples.

Crossing your female plant with late-blooming males will therefore retain the desired characteristics from your fem – instead of your cross turning into a copy of your male parent. If you’re serious about selecting the right male, make sure you have a separate room for them. As there you can leave them to flower longer, to discover more about their grow characteristics.

Hollow stems on male cannabis plants may indicate high THC-production in its offspring

Selecting the ideal female cannabis plant is easier than selecting males. As you can truly judge the fruits before you put in the labor. To guarantee a stable plant, try growing her out of seeds and cultivate it from clone too. Thereafter, you can choose the characteristics you like to see in your own creation(s). Be sure to take aroma, structure, flowering time, esthetics, taste and effect into account – as those are the most important elements to look for in a good cannabis plant. Logically, only select the best of the best females to create your own weed seeds with.

How To Collect Cannabis Pollen

Simply use a paint brush to pollinate your female cannabis plant, with the collected male pollen. [Image: Gracie Malley / Cannabis Now]

Be sure to keep an eye on them once they start flowering, as you’ve now produced ‘regular cannabis seeds’. This means your plants can turn both male or female when they enter the flowering stage. Providing you with what you need to further stabilize your creation into the perfect weed strain.

Creating own cannabis varieties is pretty easy too and could potentially be a green goldmine. Even if you don’t create the next Super Silver Haze on your first try, it is still worth trying. Cross-breeding your own weed strains is very educative and results in a huge collection of cannabis genetics. Meaning you might hold seeds to strains that are no longer being produced – to cultivate or cross-breed with.

Pollinating your female cannabis plants is as easy as collecting male pollen. Preferably wait until the plant(s) you want to fertilize are three to five weeks into their flowering period. Then take the selected female out of the grow room, again, to avoid uncontrolled pollination of the rest of the plants. Label one or more branches to fertilize, to know which plant was crossed with which and when. And use a clean (paint) brush to apply the pollen on one or more branches for seed production – leaving the rest of the flowers to produce seedless weed: sinsemilla.