Scarification, or scuffing the shell, can also help water pass through an older seed’s tough outer shell.
As cannabis seeds age, their protective outer shell hardens and prevents water from passing through. Unless the tiny, dormant embryo that lives inside the shell detects moisture, it doesn’t know that the conditions are right to sprout. As a first step, pre-soak your old cannabis seeds for about 12 hours to see if that does the trick.
In a life or death situation, surgery may be the only option. Meaning—only do this if nothing else has worked because this technique ruins as many seeds as it saves.
When your old cannabis seeds don’t want to pop, one of these four techniques could come to their—and your—rescue. Aging seeds are more difficult to grow than fresh ones and we’ll explain what you can do to help germination.
If you’re going to keep seeds more than a year or two, proper storage will dramatically increase the chances of late-stage germination. Place them in an airtight container. Put the container in a refrigerator set at 6–8°C with 20–30% relative humidity. If excess moisture is a concern, add silica gel packs to the container.
For stubborn seeds, place them in a glass of water with a few drops of hydrogen peroxide for about 24 hours. The hydrogen peroxide will help break down the outer shell and get water into the sprout where it’s needed. Once the seeds are done soaking, take them out of the mixture and rinse, then follow up with the soil or paper towel method.
When all else fails, you may need to score (scratch or cut) the outer surface of the seed by mechanical means. This can be achieved in two ways: With sandpaper, or a steady hand and a sharp knife. If you’re going the sandpaper route, line a small container, like a matchbox, with fine grain sandpaper. Pop your seeds, around 30-60 at a time, and shake the container for a good three minutes. For the knife method- use an extremely fine blade, such as found on Exacto knives or scalp to create a shallow cut in one side of the seed.
Another way to coax the shell to break down a bit is to add some fulvic acid to your original water source. A concentration of about 10ml/L is suggested. Fulvic acid is a natural component of healthy soil. It’s an organic polymer that is extracted from humus. It helps further facilitate the breakdown of the marijuana seeds outer shell and also encourages healthy plant growth.
Water & Hydrogen Peroxide
In order to store seeds correctly, you’ll have to provide them with a cool, dry environment. The idea here is to prevent the seeds from trying to germinate before you’re ready to stick them in the ground. Light, water, and heat are all things that help seeds sprout, so it should come as no surprise that you’d need an almost total absence of these things in order to store seeds for long periods of time.
As they say, not all heroes wear capes, and absolutely zero of them toss old seeds.
Germinating old seeds can be difficult, if not impossible, if it’s not done exactly right. That being said, it is possible. So before you toss those marijuana seeds that you’ve been keeping at the bottom of an old baggie, be sure and give this a read. But, let’s just start with how to store seeds the right way, so you won’t have to bust out those superpowers next time.
Tried and true, Mother Nature seems to know what she’s doing. This method is pretty much how it’s done with just about any type of plant, not just marijuana seeds. Essentially- you plant the seed. Water. Wait. Pretty straightforward.