• 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.
If you’ve tried all our tips above and still haven’t managed to germinate your seeds, it’s likely they are beyond the point of return. To avoid having the same problem next time, here are some tips to help you store your seeds:
TRY SCARRING YOUR SEEDS
One of the main reasons old cannabis seeds don’t germinate is because they tend to have a very hard outer shell. Now, cannabis seeds naturally have a hard shell that helps protect them until the conditions are right for them to germinate. Over time, however, this outer shell can become so hard that it inhibits the seed from germinating altogether.
1. Place 2 pieces of paper towel inside a salad plate.
2. Dampen the paper towels and place your seeds on top of it.
3. Cover the seeds with another 2 pieces of damp paper towel, then cover the salad plate with another plate, and keep it in a warm, dark cupboard.
4. Check on your seeds every 2–3 days.
Before you start, it’s important you remember the following:
Removing the ridge not only makes it easier for the seed to open, it helps with water absorption.
The seed’s shell is made up of two pieces, with a seam going all around. The side that’s raised more than the other is the ridge. A hardened ridge can make it difficult for the seed to open. To remove the ridge, run a sharp blade along the ridge on both sides. Handle gently and it should come off without damaging the inside of the seed.
Scarification, or scuffing the shell, can also help water pass through an older seed’s tough outer shell.
3. REMOVE THE RIDGE
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.
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.
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.
Keep the water warm, but not too hot. Aim for around 22°C. Avoid direct sunlight, and keep an eye on the glass. Do not soak seeds for prolonged periods, more than 24 hours can deprive them of oxygen and make them drown.
Please keep in mind that this particular method of germinating old cannabis seeds is a bit risky, as are the techniques described below.
This will be enough to make a lot of tiny scratches on the protective outer layer of the shell, allowing moisture to get inside much more easily.
The problem with these stimulators is that you never know the correct dosage. The information shared on marijuana forums is anecdotal, and legitimate studies have only been performed on other crops. So, if you decide to use any of these additives, do some research or ask other growers, and always err on the side of caution.
4. Remove the Ridge
The problem with very old seeds is that their outer shell dries out over time, and it gets more and more difficult for water to penetrate them. As such, you, the grower, must take some steps to facilitate this process.
Another method of making the outer shell more penetrable is scarification, and the most straightforward way to do this is to use sandpaper. Take a matchbox and line its inside with sandpaper, or roll a piece of sandpaper into a tube. Then, place the seeds inside and shake them for a minute.
Some people buy a special cracking tool for old cannabis seeds. This simple contraption applies mild pressure on a seed until an audible crack is heard. Others simply bite on the seed—ever so gently—until they hear it crack.
Instead, take a glass of water and throw your seeds into it. Twelve hours will be enough for the shell to soften a little and the water to finally get inside and wake up the embryo. Don’t forget to check the seeds regularly. As soon as they crack and the taproot appears, you should take them out. Seeds are living organisms and they need oxygen. Leave them submerged for 24 hours or more, and they may drown.