Everyone who grows from seeds wants to know how to get the fastest, healthiest cannabis sprouts. To give plants a strong start, commercial and home cultivators should prioritize improving cannabis germination techniques. Scarification is one method.
What is scarifying cannabis seeds?
Scarifying is a general term for treating seeds with chemicals or physically altering them to make it easier for the seeds to sprout.
Why scarify cannabis seeds?
Seeds need to survive the conditions of their natural environment to continue the species. Plants evolved a seed structure that protects their precious genetic contents until it is ideal to grow.
Cannabis seeds have a hard, water-resistant outer shell. This hardness increases with age, making cannabis seeds harder to germinate, even when properly stored. Scarifying older seeds and those with hard and thick outer shells can speed up the process of germination. This saves time and lets the seed use more stored energy to grow into a young plant.
Scarifying is also helpful when growing more than one variety of cannabis. Treating all your seeds with the same technique encourages consistency in germination and growth – helping everything grow simultaneously. Synchronized germination also makes managing environmental cleanliness easier and provides ideal growing conditions.
How many types of scarification are there?
Scarification techniques usually do one of two things. First, they signal seeds that it is time to start growing. Second, they speed up the process of emergence (when the new sprout breaks out of its shell) by physically removing some of the protective parts of the seed.
Many factors have affected the evolution and adaptation of seeds of different species. Although there are many subtypes of cannabis found in nature (and in nurture!), the general anatomy of cannabis seeds includes certain unavoidable qualities that you must address before growing.
Two types of scarification benefit cannabis:
Chemical scarification treats seeds with a specific, usually very dilute, solution, like hydrogen peroxide and bleach. This method is common for seeds that rely on wildlife to disperse them. It mimics the natural process of passing through the digestive tracts of animals or birds. Chemical scarification can also help trigger the internal biological processes that happen as a seed begins to germinate.
Mechanical scarification techniques cause physical damage to the hard outer shell of a seed. These may include mimicking environmental friction (like being dragged over and pushed into the soil by wind, water, or animal feet). It may also remove some of the seed’s tip to lessen the effort needed to break the shell open from the inside.
Both chemical and mechanical scarification can soften a seed’s outer shell, letting water penetrate it more easily. Soaking up water (called imbibition) is necessary for signaling and promoting the seed’s growth.
Thermal scarification is another type of scarification that includes treating seeds with heat. This method is less commonly used for cannabis. If you want the best cannabis seeds which you can use your preferred scarification method on, get some in our seed deals below!
Why are some cannabis seeds more difficult to sprout?
For growers that don’t live close to the equator, cannabis is a summer annual flower. Cannabis plants make seeds during the last weeks of warm weather and enter a period of dormancy. This dormant period is a bit like hibernation. The seeds slow their metabolism to survive a cold winter.
Seed producers use climate-controlled environments to support the development of healthy internal seed structures. A spring temperature change from cold to warm signals cannabis to ‘wake up’ and begin germination.That’s why seed producers must maintain conditions to prevent mature seeds from experiencing confusing germination triggers.
Age can impact this process. Older seeds have been in their dormant state for a longer time. This “dormancy” becomes more difficult to “break” as time passes.
Stratification can treat cannabis seeds with cold to mimic this changing condition and help them break dormancy.
What can go wrong with marijuana seed scarification?
In life, it sometimes takes a little push and an experience of discomfort for growth to happen. Because scarification essentially involves actively injuring or disturbing a resting seed, it requires great care.
When using chemical scarification methods, you risk damaging the interior structures of the seed at the cellular level and interrupting the natural progression of growth. This could be from soaking too long or in a concentration that is too high. Prevent errors by setting timers if you need reminding, and double-check your mixing ratios. Keep in mind some surface disinfection methods slow down the germination process.
Mechanical scarification can harm a delicate plant embryo (the tiny beginnings of a sprout inside a seed). Do not let physical cuts go beyond removing only the outer-most part of the seed’s protective shell. In other words, don’t cut or grind too deep.
If done incorrectly, either of these methods can lead to stunting or a complete failure of the seed to grow. Making seeds vulnerable in these ways also opens them up to infection by pathogens (things that cause diseases). To minimize this risk, it is important to be as clean as possible when handling and planting scarified seeds.
How to scarify seeds for faster germination
Recently, breeders utilized machine learning (delivered by AI) to develop “best practices” for cannabis scarification. The method revealed by this research supported the commercial production of cannabis sprouts created with in vitro seed germination in a laboratory environment. The germinated seeds provided sterile genetic material for propagation (test tube baby cannabis!).
These professional growers found that combining chemical treatment and using a scalpel to remove the seed tip (sometimes called ‘nicking’ seeds) resulted in faster germination and a higher success rate overall.
Commercial germination methods vs. home-grow: differences in need and deed
Commercial agriculturalists use diverse methods when growing cannabis plants. Although learning from how the pros grow is often beneficial, it’s also important to recognize how their resources and desired outcomes differ from your own.
In the AI-recommended method, the mechanical step of tip removal sped up emergence. It also outpaced any potential damage caused by using chemicals as part of the necessary seed surface sterilization procedure.
The Best (Professional) Method of Cannabis Scarification
Here’s how to scarify cannabis seeds.
In a clean and tidy environment, assemble the following:
Sodium hypochlorite (bleach)
hydrogen peroxide
Sterile glass container to hold this solution
Distilled water
Nitrile or latex gloves
Sterile tweezers for transferring seeds
Brand new or sterilized, very sharp, cutting tool (scalpel or razor blade)
A mounted magnifying lens, or magnifying glasses
Adequate light (tip: some magnifying tools made for crafting come with mounted LEDs.)
Seed-soaking solution OR sterilized transfer medium (pre-treated substrate for planting the seed)
Cannabis seeds
Next, follow this two-stage process:
Part A: Surface sterilization and chemical scarification
Wearing gloves, combine 4.6% sodium hypochlorite (bleach) and 0.008% hydrogen peroxide in distilled water
Soak seeds in this solution for 15 minutes.
Surface sterilization and chemical scarification is one of the most famous methods of scarification for cannabis seeds
Part B: Mechanical scarification (“nicking”)
Using magnification, observe the seed through your magnifying glass. Identify the correct place to cut. This will be the end of the seed opposite to the small scar left where the seed was attached to the plant. The point is called the “stylar end”; it’s where the radicle wants to push through.
Holding the seed steady on a sterile surface, use your very clean, very sharp tool to remove a tiny amount of the tip of the shell. Aim to just barely expose the inner part of the seed. Cutting too little is far better than too much.
After scarifying, soak or plant seeds in your chosen germination medium.
Mechanical scarification is also known as Nicking
What a “nicked” cannabis seed should look like.
Simpler Chemical Scarification Method Using Hydrogen Peroxide
Soaking cannabis seeds in a dilute solution of hydrogen peroxide (H2O2) before sowing can improve germination rates and help maintain a pathogen-free environment for new sprouts.
Make an approximately 0.5% hydrogen peroxide solution by mixing 6 parts distilled water with 1 part household H2O2. This is usually sold at 3% concentration – double-check the label to ensure your math is correct. This solution contains enough H2O2 to activate some of the seed’s germination triggers while avoiding the toxic effects it can have in higher proportions.
Soak seeds in this solution for 16 to 20 hours, then transfer them carefully to the growing medium of your choice.
Lower-risk Mechanical Scarification Method (“Scuffing”)
Scuffing helps a seed absorb water more quickly by creating small scratches in its glossy shell coating.
Use a new piece of fine grit sandpaper or a clean nail file and a soft touch to remove a bit of shine from each seed. To scuff several seeds at once, line a small container with sandpaper, place your seeds inside, and give it a brief shake.
Although imprecise, you may find scuffing easier and safer to do than nicking seeds.
Scuffing is a lower risk scarification method for your seeds
If done correctly, your “scuffed” cannabis seed’s outer shell should look something like this.
Cannabis Scarification Tips
Work quickly and confidently, exposing the scarified seed to air and surface contamination as little as possible while going through the scarification and planting steps.
Practice nicking on low-cost seed. Depending on where you live, viable industrial hemp seeds may be available. They typically command a much lower price-per-seed when compared with prime, cannabinoid-rich cannabis. You can also practice on other seeds, like oilseed sunflower, to get a feel for how to cut seed tips without damaging the inside parts.
Split the difference: if you have plenty of seeds, scarify some, but not all. If something is wrong with your growing environment or the seeds themselves, neither the scarified nor the non-scarified seeds will germinate. If you’ve done everything correctly, all of your seeds should grow. You can measure the benefit of your scarification technique by whether the scarified seeds germinate faster than those you left alone. If the non-scarified seeds germinate, and the ones you scarified fail to grow, you were too rough. In this case, you will at least have saved a few from yourself!
Conclusion: should I scarify my cannabis seeds?
Cannabis seeds recently bought from reputable seed banks do not always require scarification to germinate. High-quality cannabis seeds made for home growers are usually produced in environments that do not expose the plants to harsh conditions. The plants ‘expect’ to find a welcoming seasonal home for their progeny. These seeds are adapted to a happy medium between survival and ease of germination.
Don’t default to scarification if you have:
Fresh, high-quality cannabis seeds
Patience to wait and ample opportunity to watch seeds while they take the time they need to germinate
General cleanliness, appropriate temperatures, and undisturbed space for seeds to sprout
If you have met all of those conditions and feel the seeds are being stubborn, or you have older stock, use a scarification method that best matches your situation.
Careful, well-resourced growers can realistically achieve speedy and consistent germination using the professional scarification method as described.
If you have difficulty seeing or gripping small seeds and/or a restricted budget, use the hydrogen peroxide soak or scuff hard-shelled or aging seeds.
Final thoughts
When growing good quality cannabis seeds at home, there’s no reason to feel scarification is necessary. Most cannabis is grown by direct planting, and young plants thrive in a stable, natural, or nature-mimicking germination environment.
The researchers who developed the ideal scarification method noted that their surface sterilization process might have eliminated beneficial bacteria that would normally help the seed soak up water by digesting part of its outer shell.
This highlights the importance of recognizing the role of unseen, natural factors in healthy cannabis growth when absolute sterility is not needed (as it is for laboratory cultivation).
Until next time, may you and your garden grow together, higher and higher! Don’t forgot to grab our Grow Bible below for the latest tips!
Used sources for this article
Machine Learning-Mediated Development and Optimization of Disinfection Protocol and Scarification Method for Improved In Vitro Germination of Cannabis Seeds | Marco Pepe, Mohsen Hesami, and Andrew Maxwell Phineas Jones et al. | Department of Plant Agriculture, Gosling Research Institute for Plant Preservation, University of Guelph.| | 6 November 2021 | Plants 2021, 10, 2397. https://doi.org/10.3390/plants10112397
Seed Quality and Dormancy of Hemp (Cannabis sativa L.) | Elias, Sabry G.; Wu, Yea-ching; and Stimpson, David C. | Oregon State University. | 2020 | Journal of Agricultural Hemp Research: Vol. 2: Iss. 1, Article 2. |https://digitalcommons.murraystate.edu/jahr/vol2/iss1/2|
Different Modes of Hydrogen Peroxide Action During Seed Germination | Łukasz Wojtyla, Katarzyna Lechowska, Szymon Kubala and Małgorzata Garnczarska Department of Plant Physiology, Institute of Experimental Biology, Adam Mickiewicz University in Poznan, Poznan, Poland| 04 February 2016 | Frontiers in Plant Science 2016, 7: 66. | https://www.frontiersin.org/articles/10.3389/fpls.2016.00066/full
Baskin CC, Baskin JM. Seeds: Ecology, Biogeography, And, Evolution of Dormancy and Germination (2nd Ed). Academic Press; 2014.
Small E. Cannabis: A Complete Guide. CRC Press; 2017.
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