Sunday July 26, 2020
By Paul Barach
Now that everyone has so much free time on their hands, many pot fans are starting to look into growing their own supply. After all, how hard can it be? Nature does it all the time, and it doesn’t even have any grow light options other than the sun. While you may not be producing showroom quality nugs, there’s a pride that comes with tending to your own garden and snipping buds straight off the branch. Plus, you can’t beat the price.
Plenty of online stores sell seeds so it’s pretty easy to pick your favorite strains to start. However, if it’s been a while since your seeds arrived and they’re not yet planted, you can forgive yourself for wondering if maybe you’ve waited too long. Whether you are a cannabis fan who has just begun growing a couple of plants recreationally, or you are looking to test your green thumb for the first time, there is one question that’s going to come up at some point.
Do Cannabis Seeds Go Bad?
First off, cannabis seeds are the same as many other plant’s seeds. A waxy outer shell called the seed coat protects the embryonic shoot, stem, and root contained within, which are nourished by nutrient-rich oil sac. As long as the shell remains intact and the plant inside doesn’t dry out or get damaged, your seed can still grow into a cannabis plant.
However, this shell will not last forever. Once it dries out and hardens the seed coat can crack and expose the embryonic plant to damage. Or the seed coat hardens to the point that it no longer lets in moisture. In both cases, the seed is no longer viable.
Of course, there is some debate in the cannabis community over how long a seed can be stored. Some growers claim that when stored in the ideal conditions, seeds can last anywhere from six months to a year after packing and still spout once placed in the soil. Other producers believe that seeds are still viable up to a decade if properly refrigerated in the right containers. Most agree that on average three to six years is a maximum for viability, and every day that the seed is stored drops the chances of it germinating just a little bit.
In general, six months is the maximum if you’re looking for a nearly 100% germination rate. After three years, you’re looking at a germination rate of around 50%.
What constitutes “ideal conditions” for cannabis seed storage also depends on the genetics of that particular plant. Some cannabis strains produce a much hardier, longer-lasting seed that can go years and still stretch their leaves once planted. Others produce seeds that need to quickly return to the soil.
How Cannabis Seeds Are Stored
But when it comes to storing seeds long term, there are four main factors to consider:
Temperature is the main factor when it comes to storage. In nature, heat tells the seed that winter’s over and it’s time to start sprouting. If your seed’s not in the soil, this means that the plant matter inside the seed will begin to germinate and then rot.
41 degrees Fahrenheit (5 degrees celsius) is the absolute warmest you want your storage spot to be, with the sweet spot being somewhere around 38 degrees Fahrenheit.
If you are refrigerating your seeds, it’s best to be in a separate unit or a spot near the back. Every time you open your fridge you are changing the temperature which can harm the seeds over time.
Humidity is also your enemy when it comes to long term storage. When a seed gets wet, it cracks open to allow the sprout and root out. This will let in rot if the seed isn’t planted. A humidity level of about 5% is the maximum you want to allow.
Much like heat and humidity, light tells that seed to wake up because it’s time to spring forth.
By keeping your seeds in a dark or opaque container, they’ll keep dozing long term. Light can also damage the surface of the seed, which in turn will damage what’s stored underneath.
Besides being dark, you want to expose your seeds to as little oxygen and carbon dioxide as possible. These gasses are what growing plants breathe, as well as the pests that consume them. If you’re refrigerating or freezing your seeds, make your container as airtight as possible. If you can vacuum seal them, even better.
Alternatively, if you’re planning on planting in the next few months, regular mailing envelopes will do in a pinch. They’ll keep the seeds out of the light and dry, so all you have to do is store them in a cool place. Plus, envelopes make it easy to label your strains so that you can keep them separate.
How to Tell if a Seed is Healthy
But what should you do if you find some old seeds and have no idea how long they were stored? Maybe they were buried in the back of a closet where you used to keep your grow. Maybe past you put them in a freezer bag in the hopes of keeping your favorite strain alive, or found a couple at the bottom of a baggie that the trimmer missed. How do you know if your seed is healthy and viable to grow into a plant? There are four easy ways to check.
If your seeds are dark brown, black, or gray, that’s a very good sign. The shell is intact and uncompromised, which means the genetic material inside has been kept safe. Viable seeds should also have stripes or spots all the way around. If the seeds are white or green, they’re most likely still immature.
Check if the seed still has a waxy coating. A healthy seed should have a slight sheen to it, as though it’s been oiled. This means the seed still can retain moisture.
If the seed is still healthy, you should be able to lightly squeeze it without it crunching between your fingers. If the shell has no give and splits or splinters under light pressure, then it had no chance in the soil.
Cracks or Holes
If there are any cracks or holes anywhere on the shell, the seed will most likely not sprout. Bacteria and other harmful lifeforms can find their way into the seed, or it will dry out.
The True Test of a Cannabis Seed
Of course, the best way to test whether your seeds will sprout is to plant them and see. If some green shoots climb their way out of the soil after a couple of days or weeks, you’ve got your answer.
Storing seeds is a great way to make sure you always have your favorite strains on hand, as well as to keep yourself stocked up on plants for the long haul. Luckily, seeds can be stored for years as long as you make sure your seeds are cool, dry, airtight, and out of sight. There’s no better time than now to learn a new skill, so let’s see how green your thumb can get.
How do you like to store your seeds? Share your thoughts in the comments!