How to Rescue and Germinate Old Cannabis Seeds

Saving cannabis seeds is a widely used method for preserving genetic varieties that one has particularly enjoyed or that worked very well when planted. Therefore, growers often store some seeds for many years. 

However, over time seeds lose their germinating power. This means that, after a few years, when farmers prepare to plant them, they run into problems getting them to sprout. To prevent this from happening, and to once again enjoy that cannabis you found worth storing, there are a number of tricks. 

The key: the storage conditions

First, you have won half the battle if you were careful with the original storage. Seeds must be kept in a cool, dry place. Therefore, the best option is to store them in refrigerators at a temperature between 6 and 8 degrees Celsius, and with relative humidity levels between 20% and 30%. And sheltered from light, of course.

For all this you will need an airtight container or canister, or an opaque plastic bottle in which, in addition to the seeds, you should place little pouches of silica gel, to reduce the moisture. With regards to the best place in your refrigerator, the crisper is a good choice, as it is a little warmer than the rest of the fridge. Also, one last tip: if you store several strains in different bottles, it is a good idea to label them, so that you won´t have to open them to see which is which when you decide to plant them. 

Hydration to trigger germination

If you have only saved the seeds for a year and a half, they should not give you any problems. After this time period, even if you have stored them properly, germination may be more complicated because the older the seeds are, the harder their shells, so the water used to open them will take longer to penetrate them. Therefore, the first method to try to get the plant's embryo to develop is to put your old seeds in a glass of water, with a few drops of hydrogen peroxide, for 24 hours. Hydrogen peroxide softens the shell and facilitates the water's infiltration.

But you must be careful: the liquid must not be cold, but rather at a temperature of around 22° C. And you must keep the container away from major sources of light. During the 24 hours that the seeds are there you will have to keep a very close eye on them in order to remove them quickly if they open, so they don´t "drown."

Because of this risk, there are growers who choose another way: germinating their seeds with the help of wet paper towels and dishes. If this method is chosen, you'll have to grab a plate and place a soaked paper towel on it. After placing your cannabis seeds placed on top, with enough space between them, cover them with another damp paper towel. Although this method is widely used, some purist growers insist that you have to be very careful, because the towels used may contain chlorine and chemicals that could impede germination. 

For those beginning with the glass of water, the second step would be to move the seeds, after 24 hours, to the wet paper towels. Germination normally takes between 48 and 72 hours, and, in the case of old seeds, can last up to 5 or 6 days, or even weeks. Therefore, transferring the seeds to wet paper gives you more peace of mind, as you are dealing with less water and, if they open, they will not quickly drown. 

Other good choices for germination

There are growers who prefer their seeds to germinate directly in the soil. In this case, in addition to ensuring that you have light and well-nourished soil, you can choose to dilute 10 ml (a teaspoon) of fulvic acid per litre of water, and use it to water the site where you have planted the seed. Another option is to use slightly carbonated water, as the additional CO2 will help the liquid penetrate the seed, causing it to germinate. It is also possible to use enzymes or germination enhancers, designed to help seeds open and develop in those first stages. 

Another good investment, which can be key in the case of old seeds, is Jiffy 7. This product is a compressed pill of dried peat that you need to soak for a few minutes. At this point it becomes a small sack of soil that is specially designed to facilitate germination, because it features the ideal structure, is sterilized, has all the necessary elements to nourish the seedlings during the first week, and is pH-neutral. Due to these characteristics it can be your best bet to get your older seeds to sprout. 

Last resorts to save your seeds 

If all else fails, there are still a few more aggressive tricks that should only be used when, after a few days, your seeds have failed to hatch and make their way into the world. 

For example, you can scrape off the outer layer of the seed with a little sandpaper, creating micro-abrasions that should let some water in. So you don't overdo it with this scraping we have a little trick: roll up a piece of very fine sandpaper, with the rough side on the interior, and secure it with tape. Place the seeds inside and cover the openings with your hands. Then just shake it for a couple of minutes and the sandpaper will do its job. Another more risky option is to use a knife to cut the seed transversely, ever so slightly, which will help the water penetrate the shell. 

If these methods work and get your seeds to break, allowing the embryo of the cannabis plant to emerge, you will have achieved your goal. You'll have to be very careful when handling them during the first few days, but after a week your old strain, preserved for years, should grow just like a younger seed and, after a few weeks, offer the same harvest you got from it before and so fondly remember.