How to make your own weed strain

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How do I breed my own strain?

Have you been shopping online for cannabis seeds and thought to yourself? “hmm I wish this seed bank would just cross Zkittlez and Runtz” (or whichever your two favorite strains are). Well once you have mastered the art of growing marijuana at home you might want to get a little bit creative and learn how to make your own weed strain.

Believe it or not cannabis breeding is actually a lot more simple than you might think. All that is required is a healthy male and female cannabis plant and a little knowledge on selective breeding.

What is a dioecious plant?

Cannabis is a dioecious plant which means that each individual plant has its own gender, male or female. For breeding purposes therefore, a grower needs to use regular cannabis seeds that have the ability to produce both genders. Regular cannabis seeds are produced in the very same way that they would be in the wild. The seeds have roughly a 50:50 chance of growing into a male or female plant. 

If you are reading this and thinking that ‘cannabis can also be hermaphrodite’ you are correct. Although it is a dioecious plant, any male or female that is stressed could partly change gender and turn “hermie” on you. 

How are cannabis new strains created?

To create new breeds of cannabis, you need to start with both a male and female plant. Female plants produce flowers and male plants produce pollen. Once male plants reach maturity their pollen sacks will burst and spray their pollen on the surrounding female plants. This then pollinates the female flower, and it begins to create seeds.

To breed cannabis plants, you will need to start with a male and a female plant. The male plant produces pollen, which is collected and used to fertilize the female plant’s flowers. Once the female plant has been fertilized, it will begin to produce seeds that will have half of the female and half of the male parent genetics. 

How do I choose which strains to breed?

Generally speaking the choice is completely yours and there is no right or wrong genetic cross. However, you should think carefully about the characteristics that you want your new strain to hold. For example, if you want it to be high yielding then you might choose Big Bud, whereas if you want it to be high THC you might choose Gorilla Glue. The beauty of breeding is that you can choose to cross Big Bud and Gorilla Glue to make a huge yielding, highly potent creation of your own.

What you need to be aware of is that by breeding two cannabis strains you are combining their genetics. This means that any undesirable traits will also be passed down to the offspring so it is best to only breed with plants that you are 100% happy with. If you are growing a plant that gets easily stressed, does not respond well to training or is susceptible to mold its best to avoid using this to breed with. Most professional breeders will produce generation after generation of a single variety just to pick out the best and most stable versions to breed with.

What are the best cannabis strains to breed with?

With all of this in mind let’s assess some cannabis strains, compare their characteristics and try to find the perfect pair for you to create a new cannabis strain.

Highest yielding strains

High Yield StrainsYieldIndica/SativaUSP
Big Bud600 g/m2+IndicaHuge yields
Super Lemon Haze600 g/m2SativaCitrusy taste
Durban Poison600 g/m2SativaLandrace
Purple Punch600 g/m2IndicaVibrant colors

Highest THC strains

High THC StrainsTHC LevelIndica/SativaUSP
Godfather OG34% THCIndicaMost potent
Gorilla Glue30% THC50/50Legendary strain
Bruce Banner30% THCSativaSativa dominant
Alien OG28% THCIndicaPotent Kush

Best tasting strains

High THC StrainsFlavorIndica/SativaUSP
GelatoFruity / SugaryIndicaPotent
Girl Scout CookiesSpicy / SweetIndicaLegendary strain
Mango KushCitrus / TropicalIndicaCalming high
CheeseCheese / SourIndicaMold resistant

Which strain is best for my climate?

One thing you should consider before breeding your own cannabis strain is where you are going to grow it. Are you growing indoors or outdoors? How much space do you have? And what is the climate like?

Indoors or outdoors

All cannabis strains can be grown both indoors and outdoors, however once you have decided whether you will let mother nature do its thing, or you will have your plants in a grow tent, you can have a think about which are best for your climate and available space. 

How much space do you have?

Breeding cannabis can be quite space intensive, especially if you decide to breed sativa dominant strains that can reach up to 20 feet tall. Most growers also use two rooms, one to grow male plants and another to grow female plants. If you are growing indoors it may be best to choose a strain that doesn’t grow too tall, or alternatively you can use plant training methods to keep it under control, or you could consider breeding an autoflower instead.

What is the climate like?

Indica strains prefer a warm temperate climate, whereas sativas prefer slightly warmer subtropical humid climates. However, due to their dense foliage indica varieties will be more susceptible to mold in hot humid environments. To combat this you could choose to cross an indica with a sativa, or you could introduce a strain such as Cheese that has a good degree of mold resistance built in.

growing cannabis plants in pots outdoors

What are dominant and recessive traits?

Cannabis plants contain two types of character traits, dominant and recessive. Recessive traits are characteristics of a plant that are less evident until another plant with the same recessive trait is introduced into the mix. For example, let’s say you grow ten plants and out of those two plants grow much taller and more sativa like, whereas the rest grow shorter and bushier. That particular strain could carry the recessive trait of being tall. This could be because although it is indica dominant, somewhere down the line it carries sativa genetics. This is common among hybrid cannabis strains that have been crossed and crossed again with other cannabis genetics.

Dominant traits on the other hand are characteristics that are more common and you would expect to see the majority of the time. Let’s take Grandaddy Purple as an example. Purple buds are is its dominant trait, but because it also contains the genetics of Skunk and Afghanistan in its family tree, the recessive trait could be that some plants produce green buds.

If you are breeding cannabis with the goal of emphasizing a particular characteristic then it is best to choose two parent strains with that trait so that it becomes a more dominant trait in its offspring.

To give you an idea of how a cannabis strains can be affected by the genetics of its ancestors, let’s take a look at the family tree of one of the most famous cannabis strains, Gorilla Glue. 

You see Gorilla Glue is a 50:50 hybrid, which we know doesn’t exist in nature, so how exactly was this genetic hybrid created? Below is a family tree representation of the strains that have gone into creating Gorilla Glue. All-in-all 17 strains have been combined over generations to make what we now know as Gorilla Glue. Hopefully this gives you an idea of just how many genetic variations can go into one plant and how this affects the dominant and recessive traits of offspring.

Gorilla glue strain family tree

What are phenotypes in cannabis?

If you were to grow ten Gorilla Glue seeds, the chances are that some will be more sativa in appearance whereas others will look more like an indica. Just because it is the same cannabis strain it doesn’t mean each plant should be identical. The different variations of each strain are its phenotypes. In layman’s terms a phenotype is just a combination of the various genetic traits that a cannabis plant exhibits. 

The phenotypes a cannabis plant contains will be passed down from its parents. For example, if you were to cross Green Crack and Grandaddy Purple, some of the offspring may carry the purple gene, others may not. This just means that each of the variations has a slightly different set of genetic traits and therefore is a different phenotype. 

Highly stable strains should display less phenotypes because they have been selectively bred with the undesirable traits bred out and the desirable traits bred into them. This means that a highly stable cannabis strain should produce plants that look more similar to one another, where they have been bred using multiple generations. Whereas if you were to breed yourself, the first generation is more likely to have varying phenotypes. This is not necessarily always a bad thing and doesn’t actually affect the quality of the weed in any way, it just simply means your plants may vary slightly from one another. 

If after breeding you want to further stabilize your cannabis strain to reduce the number of phenotypes you can do this using a number of methods such as backcrossing, selfing or selective breeding.

How to use pollen to create your own cannabis strain

Now that you understand how to select the best characteristics of a cannabis plant you can begin creating your new strain. The next step is to begin the fertilization process.

To fertilize your female plant you must first take some pollen from your male. Here’s a step-by-step guide to the process:

  1. Selecting your male: Identifying a healthy and mature male plant that has produced pollen sacs. These sacs are usually found in the nodes between the branches of the plant.
  2. Collection: When the pollen sacs are mature they could burst at any minute so its important to be very careful when collecting your pollen. This can be done by carefully cutting the sacs off of the plant and placing them into a paper bag until they burst and release the pollen.
  3. Selecting your female: Next, select a healthy and mature female plant that is in the flowering stage. This is the stage in which the plant will produce pistils, which are the female reproductive structures that will receive the pollen.
  4. Pollination: To pollinate the female plant, the pollen can be sprinkled directly onto the pistils or it can be mixed with water to create a solution and then applied using a brush or dropper. Another simple and effective way to pollinate your female is to gently brush on the pollen you have collected with a paint brush or make up brush.
brushing pollen onto a female cannabis plant to make your own cannabis strain

When you are breeding cannabis, cross pollination can also occur naturally, especially if male and female plants are grown in close proximity to each other. It is because of this that many breeders choose to grow only female plants and remove any males that appear, or to grow their plants in isolated environments to prevent unwanted cross pollination.

Joe Musgrave

Joe Musgrave is a keen 420 blogger who writes about all things cannabis. After harnessing his green thumbed skills through years of working on cannabis farms, Joe now shares his knowledge with the rest of the online 420 community.

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