Cannabis breeding is a lengthy and complicated process that takes years to master. However, that doesn’t mean it is impossible. If you are a home grower looking to try your hand at breeding on a small scale, check out our tips below and let us know how you do!
The first question you probably have, is why breed at home in the first place? Well, to put it simply, breeding different cannabis strains allows a home-grower access to new hybrids. The breeding process also assists in conserving genetics for future use. Pretty cool, right? Additionally, not all new growers can afford to purchase new seeds and genetics each season. If you have a specific strain you like and want to preserve, or if you want to try creating a unique hybrid, then breeding is the way to go.
Sexing Your Plants
First, you need to determine which of your plants are male and which are female. You can tell what gender a marijuana plant is based on what grows between the nodes (the space where the leaves and branches grow off the stalk). A male plant has a pollen sac and a female plant has a stigma, which will spread out to catch pollen.
These are visible in the pre-flower phase, approximately four to six weeks into growth. They can sometimes be hard to see with the naked eye so you might have better luck with a jeweler’s loupe.
If your plant has both the pollen sacs and catchers, then it is a “hermaphrodite”. This is common for plants under severe stress caused by bad weather or environment, plant damage, nutrient deficiencies or disease. Breeding a plant with hermaphrodite development will produce less viable spores as it has weaker genetic markers, so it is best to be avoided.
The Breeding Process
Now that you are ready to start your first home-breeding experiment, you need to choose the male and female strain you want to breed. Both plants will need to be 2-3 weeks into their bloom phase. Once you have chosen your plants, there are a few steps you need to follow and tools you will require for the process.
Before you begin, get a good pair of gloves, a small paint brush, plastic baggies and ties. Also, make sure you have an isolated chamber (such as a sealed grow tent) so as not to spread pollen to other plants accidentally. The isolation chamber is for the female(s) that you want to breed, only.
When you have these items gathered up, you can start sanitizing your isolation chamber. A clean space prevents cross-contamination or pollination and is a safe place for the plant to continue to mature. Make sure to sanitize your gloves and brush as well.
The next step is to collect the pollen from your chosen male plant. Male pollen sacs will be visible after the first week or two in their bloom phase. Quickly after that, the sacs will open and the pollen becomes available.
Once you have identified the desired male plant, remove it from general population and isolate it immediately so that you don’t accidentally pollinate non-desired female plants. Once you have isolated the male plant, use a small paintbrush to carefully collect the pollen. You can use a plastic bag or a small jar. It is best to terminate the male plant after this is completed. Make sure to store the pollen in a sealed container in a dark space – such as a freezer – to maintain its viability, if you are not going to be using it right away.
After you have collected pollen and terminated the male plant, you need to choose your female plant. Once hair-like stigma’s have developed on the flowers of your chosen female, it is mature enough to be pollinated. The more pistils that are visible during pollination, will yield more seeds once completed. The pistils that are white or off-white are the best to pollinate, if they have turned a rusty or brown color than they are too ripe to fertilize.
In order to pollinate the female, we are going to use a common procedure known as “selective propagation”. The goal with this is to place the male pollen onto specific branches that you wish to produce seeds; each can produce up to 20-30 seeds! Of course, this process must be done correctly to yield maximum results. This can take some practice, but we have outlined it below to make it easier!
- Ensure a negative pressure in the isolation chamber before you begin.
Set out the bag or jar with the male pollen as well as your gloves and a paintbrush. Make sure any fans are “off” during this process so you do not spread pollen everywhere.
- Collect a small amount of pollen onto your brush – remember, a little goes a long way!
- Run the brush along the female flowers. Only touch the bristles to the tops of each stigma.
- Once the stigmas have been pollinated, seal them using a plastic bag and tie. After two or three days, the bag can be carefully removed. However, this is not necessary if you’re okay with finding seeds throughout the rest of the pollinated plant (pollen spreads easily) or if you intend to pollinate the whole plant.
- Keep your isolation chamber sealed during the entire breeding process.
Repeat this process 1-3 times over the next week or two. During the fourth week of bloom, you can cease pollination. If you wish, you can introduce your pollinated female with your other female plants. Just ensure to rinse it down to remove excess pollen. This will also help the plant breathe better.
Once you have successfully bred your plants, the next step is to collect the seeds. The seeds will be mature in approximately 4-6 weeks. You can test to see if the seeds are mature by picking one off the plant. If they are ready, it will be a dark brown or deep tan color with a hard, outer shell and a few visible stripes.
For plants that are ripe, you can wait until the life cycle has completed before harvesting your seeds. This will give them the maximum time to mature. Make sure to harvest and dry your plants before collecting seeds. If you have only fertilized select branches, versus the entire plant, leave those branches on a little longer than the crop flowers.
Store your seeds in properly labelled, sealed jars in a dark space if you are not using them right away. It is best to store them in a fridge or freezer. When you are ready to use them, take them out and give them a chance to acclimatize in their jar for 24 hours before planting.
Breeding your own plants and generating seeds is a great experience to add to your cannabis library. It may take a few tries to get the hybrids that you really want, but for anyone who wants to spice up their home-grown garden, this is a great way to do so and to create something new in the process!