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Grow Guide

How To Germinate Old Cannabis Seeds

How To Germinate Old Cannabis Seeds

Old seeds can be hard to get going, but it is possible. Using our following methods, you can salvage a lot of seeds that would have otherwise ended up in the bin.

There is nothing more frustrating than trying to germinate your cannabis seeds to only find that they have grown too old. Fortunately, all is not lost and it is not necessarily the end for your seeds. Using the following techniques, the great majority of old seeds can be salvaged.

The problem with old seeds is not that they have become old per se, but that their ability to absorb water through their shell has diminished as they have hardened with age – also making it very hard for them to split open. In order to overcome the problem of old seeds not germinating, you need to overcome the problem of poor absorption – there is still life in them seeds! The process we are about to explain is called scarification.

Scarifying Your Seeds

Scarifying Your Cannabis Seeds

As the name suggests, scarifying is the process of wearing away the shell, so the first thing you need to is scuff your seeds. To do this line a small matchbox with sandpaper. Put your seed(s) in it, and shake it around for 30 – 60 seconds. This will cause micro-abrasions on the shell surface, making it much easier for it to absorb water.

Hopefully, this will be all you need to do in terms of scarification, but if worst comes to worst, there are two more steps you can take. The first of these two steps is to remove the seed’s ridge. Look at the edges of your cannabis seed. Notice how the seam holding the shell together goes all the way around, but one side is more pronounced than the other. This pronounced ridge can make it much harder for the seed to open up, but can be easily removed:

Take your seed between your thumb and forefinger, and with a sharp knife, very gently run it along the ridge at a 90-degree angle. The ridge should come away, exposing the seed beneath. Carefully turn the seed around, and dislodge the ridge at the other end of the seed so it fully falls off. Now that this is done, you should be able to germinate your seeds as normal.

A Last-Ditch Attempt

Cannabis Seeds Still Not Germinating

If they are still not germinating, they are probably done for, but as a last resort, you can run a scalpel down the one side of the seed to open it up a little. This will make it much, much easier for water to be absorbed, but also exposes it to a great deal of potential damage. It is a last-ditch attempt to salvage a seed that would otherwise be thrown away – you should never do this normally.

It is also worth noting that these scarification techniques are a bit tricky to do correctly, and should not be attempted unless you are certain the seeds won’t germinate. Any healthy, viable seed should happily germinate without the need to resort to any of these measures.

Germinating Your Scarred and Scuffed Seeds

With the seeds prepared, you can move on to the germination. There are a few ways to germinate old cannabis seeds, all of which are effective in their own right. Before we get into this though, there is one optional thing you can do to boost germination chances, and this is through the preparation of your water.

Water Prep (Optional)

Water Prep

There are two ways you can enhance your water for the germination of old seeds. Firstly, you can use lightly carbonated water. The CO2 in the water will help it to be absorbed by your tough, scarified seeds. Secondly, you can also add a bit of fulvic acid into your water, at around 10ml per litre of water. Fulvic acid helps plants with absorption and can lead to healthy growth. Alternatively, you can try using a seed germination booster liquid, which is basically a mix of nutrients ideal for germinating seeds. Although the main obstacle with old seeds is getting the water into them, a few well-balanced nutrients can’t hurt to get them going.

Soil Germination

Germination In Soil

Our favorite method - soil germination - harnesses the power of Mother Nature and starts the seed's life off just as She intended.

Firstly, place your seeds in a bowl of room temperature water. Place a bit of cardboard over the bowl, and put it into a dark cupboard overnight (12 hours). Once this is done, fill a small pot for each seed with soil – germination soil is best, as it has the right level of nutrients to get your little beauties going. Dampen the soil with water and then create a small, circular indent in the centre. This indent should be 3-5mm deep. Place each seed in an indent, pointed tip down, and then carefully cover them over with soil. Put the pots in a dark, warm room for 6 hours, and then put them under your lights and leave them on. You should see a shoot forming within a couple of days.

Note: Soaking your seed for 12 hours is only usually done with old, tough seeds. You can skip this step for most normal seeds.

Paper Towel Germination

Paper Towel Germination

Paper towel germination is another commonly used method. As with the soil germination, firstly soak your seeds in room temperature water overnight in a dark place, (once again, not normally necessary with normal seeds). Once this is done, place a couple of wet paper towels in a Tupperware container. Make sure the towels are at room temperature and then carefully transfer your seeds onto the towels. You can place the lid on the Tupperware to keep in the humidity. Mist the towels each day with room temperature water to ensure the towels don’t dry out. When doing this method it is important to a), make sure that the seeds to not become too dry, or too wet (the towels should always be damp), and b), that it is kept warm.

Once your seeds have begun to sprout, you can carefully transfer them to your growing medium of choice.

Hopefully, with this knowledge in hand, you shouldn’t have a problem breathing a bit more life into those old seeds of yours. If they are still failing after all this, then they are definitely a lost cause.