To improve your chances, use carbonated water and/or add one of these supplements that help with water absorption. Fulvic acid and most boosters also give your seeds a light dose of nutrients.
Scarification, or scuffing the shell, can also help water pass through an older seed’s tough outer shell.
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.
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.
To scarify your seeds, line a matchbox or other small container with sandpaper. Drop the seeds inside, shake vigorously for 30–60 seconds, then remove. You may not notice much of a difference, but the small micro-abrasions are sometimes enough to let water breach the shell and trigger germination.
Did you find some old seeds in a forgotten corner of the house? Well, you’re in luck; below we’ll share some simple tips to help you germinate old cannabis seeds.
Sometimes, it’s best to leave Mother Nature to work her magic on your old seeds. Try scarring your seeds a little as we showed you earlier, then let them sit in carbonated water overnight. Next, prepare a small nursery pot with some high-quality soil. Make a small hole in the middle of the pot with your finger, roughly the depth of your fingernail. Drop your seed inside the hole and cover it. Moisten the soil and keep your pot in a warm place with indirect sunlight—a windowsill works great.
BEFORE YOU START, SET YOUR EXPECTATIONS STRAIGHT
• Some seeds won’t germinate at all. Unfortunately, old seeds sometimes just don’t sprout. So, if you try all of the tips below and wait patiently without any luck, it’s likely your seeds are just too far gone.
• Seeds can take a while to germinate. While healthy, fresh seeds can germinate in just a few days, old seeds can take anywhere from 2 days to 3 weeks to sprout. So be patient.
Before you start, it’s important you remember the following:
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.
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.
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.
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.