Do Cannabis Seeds Go Bad?

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. After all, how long do marijuana seeds last? 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.

First off, marijuana 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 a nutrient-rich oil surrounding them. 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.

If stored properly, cannabis seeds can last for years and still sprout. photo credit

Of course, there is some debate in the cannabis community over how long do marijuana seeds last. Some growers claim that when stored in the ideal conditions, marijuana seeds can last anywhere from six months to a year after packing and still spout once placed in the soil. Other producers believe that marijuana seeds can last up to a decade if properly refrigerated in the right containers.

Most seed producers 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.

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 marijuana seed that can last for years and still stretch their leaves once planted. Others produce seeds that need to quickly return to the soil.

In terms of long term storage for your marijuana seeds, there are four main factors to consider:

Heat

When it comes to how long marijuana seeds last, temperature is the main factor. In nature, heat tells the seed that winter’s over and it’s time to start sprouting. If your marijuana seed’s not in the soil, this means that the plant matter inside the marijuana seed will begin to germinate and then rot.

If you are refrigerating your marijuana seeds, they’ll last the longest 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

Humidity is also your enemy when it comes to how long your marijuana seeds will last. 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.

Light

Much like heat and humidity, light tells that seed to wake up because it’s time to spring forth.

In order to keep your seeds from going bad, it's best to keep them stored in a dark container in order to avoid light. photo credit

By keeping your seeds in a dark or opaque container, they’ll keep dozing long term. Light can also damage the surface of the marijuana seed, which in turn will damage what’s stored underneath, causing your marijuana seed to go bad. 

Air

Besides being dark, for your marijuana seeds to last long term, you want to expose them 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 marijuana seeds, make sure your container is 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 marijuana 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.

What should you do if you find some old seeds and have no idea how long they were stored? 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 marijuana seed has gone bad, or if it’s healthy and viable to grow into a plant? There are four easy ways to check if your marijuana seed is still good. 

Dark Color

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.

Seeds should have a dark color. If seeds are still green they are probably not ready yet. photo credit

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.

Waxy Coating

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.

Hard Shell

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 your marijuana seed has gone bad and has no chance in the soil.

Cracks or Holes

If there are any cracks or holes anywhere on the shell, your marijuana seed’s likely gone bad and will most likely not sprout. Bacteria and other harmful lifeforms can find their way into the seed, or it will dry out.

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.

The only way to truly know if your seeds are good, is to test them out and see. photo credit

Storing marijuana 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, marijuana seeds can last 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 Tell If a Seed is Good or Bad?

If the seed is dark with stripes or spots all the way around, has a waxy shell that doesn’t crack when you give it a light squeeze, and doesn’t have any visible cracks or holes, it’s probably still good. If there are holes in the shell, it’s dry, or especially pale, your marijuana seed’s probably gone bad.

Do Autoflower Seeds Go Bad?

All marijuana seeds can go bad, including autoflower seeds. However, by keeping your seeds at a stable 38 degrees Fahrenheit and at around 5% humidity, as well as airtight and out of the light, your seeds may last up to 5 years or more. 

How do you like to store your seeds? Share your thoughts in the comments!