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.
This is a very popular way to germinate seeds. And for good reason; it’s pretty successful. Here’s how to germinate your cannabis seeds using paper towel:
TRY GERMINATING YOUR SEEDS IN CARBONATED WATER
• 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.
Old cannabis seeds can be hard to germinate. Luckily, there are a few techniques that can help them sprout, even if they’ve been forgotten for some time.
Try dropping your old seeds into a glass of sparkling water. The CO₂ in the water should help the seeds absorb more moisture, encouraging them to sprout. You can also add some fulvic acid to the water to help break down the shell of your seeds. You’ll only need about 2.5ml of acid for a glass of sparkling water (roughly 250ml).
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.
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.
4. SLICE THE SEED
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.
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.
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.
We usually start all of our seeds off this way even if they are newer seeds.
The pre-soak method is one way to kick start your old cannabis seeds into sprouting.
The next step is to put them either in a Pre-soak, paper towel method, or grow medium of your choice soil coco, rockwool.
Especially if they are not wanting to crack open. About 50 to seventy 75 percent of the time this can be the case.
I have tried various ways to get older seeds to sprout, some successful some not.