Many growers get frustrated when their seeds are slow to germinate or don’t germinate at all. Marijuana seeds naturally have a thick shell to protect them from the elements and sometimes all they need is just a little help. You can greatly improve or speed up the weed seed germination process by using a method called scarifying. Scarifying cannabis seeds has proven to increase germination rates and help even the most stubborn seeds sprout. Here we’ll show you how to scarify cannabis seeds.
What is scarifying?
Scarifying means to nick, scratch, or mar the surface of the seed to be more permeable. This helps water and oxygen enter the seed and reach the embryo. Without proper scarification, seeds can take weeks, if not months, to sprout.
Cannabis seeds have what some describe as a ‘harsh’ outer shell that makes them hard to crack open. The cover does this for a reason, helping protect it from birds and other animals who may want to eat it. When you’re trying to grow, this hard shell is almost like a blockade between you and your plant baby. Your goal is to scarify your seeds to make them grow faster.
How does scarifying speed up weed seed germination?
There are many reasons why cannabis seeds won’t sprout, but a big, most common culprit is the lack of hydration. Once you’ve cleaned and disinfected your weed seeds, they should be ready to soak in some water for roughly 24 hours. But some varieties can benefit from a slightly different approach. For large seeds (i.e. Blue Dream) or ones that tend not to break dormancy quickly, scarifying can help you get a jump-start on germination rates.
When you’re looking for tips on improving your germination rate, it’s essential to understand how seeds typically sprout. It all begins when the outer shell, or integuments of the cannabis seed, break down as it interacts with moisture. The embryo cells then become turgid and begin to grow, causing the radicle and plumule to emerge into the world!
Scarifying cannabis seeds helps to reduce the hard impermeable outer layer, which doesn’t allow water and nutrients to get through. This is done by mechanical or chemical means, and in both cases, you should do it before sowing the cannabis seeds into a growing medium.
Step by step how to scarify marijuana seeds
Cannabis seeds have a firm outer shell to survive adverse conditions for decades in the wild. To encourage proper germination of cannabis seeds, you should scarify first. There are plenty of ways to scarify the cannabis seeds. For thinner-than-usual pods, nicking or rubbing may be enough. For thicker pods, soak them in boiling water for a few hours. You can also use rubbing alcohol or any other strong acid solution.
Mechanical scarification, more commonly known as nicking, involves cutting or breaking the outer layers of the seed coat with a sharp tool. Use a thin-bladed knife or other sharp objects. Stay away from anything that would damage the embryo, such as a saw. By removing only a few outer layers of the endocarp (seed coat), you allow water and nutrients to penetrate the embryo to help it sprout.
Chemical scarification is the exposure of plant seeds to acids or bases to break down the seed coat. Whether it’s through soaking or boiling or using alcohol and glycolic and lactic acids, you can increase your seed’s chances of germinating.
Recommended methods of marijuana seed scarification
Method 1: Scarify seeds by scraping with a knife, nail clipper or nail file
By scraping the surface of the soft seed coat with a knife or a nail clipper, you can expose more of the surface area to improve water absorption. Use caution not to cut into the embryo in the interior of the seed.
What you will need
- Cannabis seeds
- Knife/nail clipper/file
How to scarify cannabis seeds
- Find a knife or nail clipper.
- Hold the cannabis seed between your thumb and index finger.
- Scrape the seed with the knife or nail clipper as hard as possible.
- Scrape over a hard surface, like concrete or ceramic tile to remove all the seed hairs.
- Wait until most of the outer shell is gone
- Soak for 5-10 minutes
- Rinse the seeds, and place them on a paper towel
Method 2: Scarify seeds using sandpaper
Another way is to place them in between two sandpaper sheets and roll back and forth with moderate pressure. This method will nick the shell enough so that moisture can penetrate the seed, causing it to germinate.
Another way to do this that I tend to use myself is to get an empty glass or jar and line the inside with sand paper with the rough side facing inwards (see image right). Then place the seeds in the centre and swirl the seeds around for a minute or two.
You will notice the centrifugal force pushes the seeds against the sand paper lightly scraping the outer shell of the seeds.
What you will need
- Two sheets of sandpaper
- Marijuana seeds
- Jar or glass
- Cut your sandpaper
- Stick the seeds inbetween the sandpaper
- Rub or roll them back and forth
- Place in water for about 3 minutes
Method 3: Scarify seeds by soaking in warm water
Seeds can be scarified by soaking them for about 12-14 hours in warm water, which will cause the outer shell layer to split. The exact temperature of the water doesn’t matter, but you should ensure that you are not using hot water so as not to harm the seeds. As soon as the seeds are evenly colored, take them out of the water. This method is often preferred over using a sharp tool because you don’t damage or harm the seeds anyway.
What you will need
- Warm water
- Prepare water and container
- Pre-warm water to 55–70 °C
- Put the seeds inside and let them sit for up to 12 hours.
- Gently shake the seeds out while keeping the bowl upside-down.
Method 4: Chemical scarification
In this method, sulfuric acid can be used to create etched scars from chemical scarification. It’s a dangerous compound that you should handle safely with the right know-how and equipment, it’s best to play it safe. Vinegar makes a great alternative as a liquid since its properties are better suited for breaking down cannabis seeds’ outer shell. It produces excellent results too.
Make sure to pour the acid on a few samples at first; some varieties may be more difficult to penetrate than others.
What you will need
- White vinegar
- Baking powder
- A glass container
- Place some seeds in a jar.
- Cover the seeds with white vinegar for about half an hour.
- To neutralize the acid, create a solution of water and baking soda, then soak the seeds in it for about ten minutes.
- Let the seed sit in a jar of water until they are swollen.