Last Updated January 28th, 2023: With the right storage conditions, cannabis seeds can last from several months to years (up to 5 years) and remain viable. Optimal storage conditions, like we’ll learn later in this article, touch on three main factors -humidity, light, and temperature. So let’s jump right into it, how long do marijuana seeds last? And how can you extend this lifespan?
For many home growers, storing and maintaining cannabis seeds is important, especially for seed banks. Inappropriately stored seeds might not germinate and even if they do, they might not grow properly. Whether you’re growing indoors, outdoors or in your closet, you need to ensure your cannabis seeds are stored properly!
How Long Do Marijuana Seeds Last For?
Cannabis seeds can last for a few months before they go bad if they are stored in normal conditions, but they can last up to a year if they are stored in cool, dry and dark storage areas. But you can extend this life up to a decade if you refrigerate the marijuana seeds!
Essential Conditions For Cannabis Seed Storage
For your cannabis seeds to last longer, proper storage is essential. Here are the ideal conditions for storing cannabis seeds;
Light triggers the germination of cannabis seeds. For this reason, always store them in the dark. Both the container and location should be dark.
Cannabis seeds, just like any other seeds, need appropriate moisture to remain viable. Too high humidity levels make them rot and cause mold in storage while too low levels are only suitable for long-term storage.
Here’s what happens to your cannabis seeds at various humidity levels:
- 61%+ – The higher the humidity level, the more endangered your seeds are. At this level, they’ll wilt and die in roughly 12 hours.
- 31 – 60 % – This range is the germination zone especially once the humidity level passes 40%.
- 21 – 30% – This is the most appropriate range for storing cannabis seeds.
- 9 – 20% – Chances are high that the seeds will develop fungi both on the inside and outside at this level. At below 20% humidity, they start to sweat. In the right conditions, 8 – 10% is an ideal range for long-term storage.
- 8% – At this level, cannabis seeds attract pests and insects.
Similar to cannabis seeds, weed can expire as well!
The ideal temperature for the storage of cannabis seeds is 43 – 47 degrees F. Extremely lower or higher temperatures aren’t optimal for seed germination, this is generally why large seed banks keep their seeds in fridges to have them last longer.
That being said, seeds can still last quite a bit at room temperature as long as you keep them sealed and away from the light.
Best Containers To Store Cannabis Seeds
We’ve already established that proper storage of cannabis seeds is essential to how long they last. The million-dollar question that then begs is, which are the best containers and places to store the seeds?
Here are some appropriate options:
- Glass jar (ideal for medium-term storage)
- Plastic container/bags (ideal for short-medium-term storage)
- Paper envelope (ideal for short-term storage)
- Vacuum sealed container
Glass jars, such as mason jars, are the best containers for storing cannabis seeds. Those that aren’t opaque should be kept in a dark cover or location to prevent light from affecting the seed’s quality.
Ideally, choose a glass container with a tight lid. Lids made of glass are the best because other materials react differently from glass to changes in the outside environment. Doing this can result in the lid expanding or contracting relative to the glass rendering the seal weak.
I personally recommend an airtight containers such as these.
Although some plastic bags are great for storing seeds, not all are ideal as they aren’t airtight meaning they can’t prevent fluctuations in humidity, temperature, and light. Plastic bags are only effective for short-term storage.
Note: Plastic isn’t a good material for storing cannabis seeds due to its microscopic pores that allows harmful elements from the outside environment.
Paper envelopes are appropriate for storing cannabis seeds as they keep out light. Once you put seeds in a paper envelope, place them inside a mason jar.
Vacuum Sealed Container
A vacuum-sealed container is the best bet for storing your seeds for the long term. Achieve this by removing air from a Ziploc bag. Once you do that, put the sealed bag inside a dark container, then in a refrigerator.
Maintain temperature levels at between 6 and 8 degrees C or 43 – 47 degrees F.
Best Places/Locations To Store Cannabis Seeds
Just like with a container, where you store your cannabis seeds is paramount to their viability. So which are the ideal storage spaces or locations?
Cannabis seeds last the longest in a refrigerator!
A refrigerator is an excellent choice because it offers friendly conditions for the stored cannabis seeds to be viable for a long time. The only caveat is that you shouldn’t open the door frequently since it messes with the dark, dry and cool conditions.
Constant opening of the fridge causes humidity and temperature fluctuations which affect the seed’s quality.
If you can have a refrigerator that is specifically dedicated to storing the seeds, the better.
Ideally, your refrigerator should be the no-frost model.
A cool basement is a great alternative to a refrigerator. If you choose this option, have some insulation to protect the seeds from changes in temperature and desiccants for steady humidity levels.
While strange, burying your seeds underground also works. Just ensure that you dig deep enough so that changes in air temperature don’t affect ground temperature.
Similar to a basement, put your seeds in a desiccant first to maintain steady humidity levels.
A regular room in the house works fine. However, it is only effective as a short-term solution because chances are high that the temperature inside your house is higher than optimal.
Common spaces to put the seeds include in a drawer, cupboard, or closet. Ensure the seeds are not only undisturbed but also in darkness.
Indications That Cannabis Seeds Are No Longer Good
Assuming you’ve stored your seeds for long, is there a way to know if they’ve lasted or are no longer good?
Although many seeds look just fine and won’t germinate, several indications tell they haven’t lasted.
Holes or Cracks
Cracks in the seed are a major indication that your seed hasn’t lasted. Cracks on the outer shell mean the seed is no longer viable. Exposure of the genetic material inside drastically reduces their chances of germination.
The second indication is the outer shell. If you observe that it is pliable in such a way that you can squeeze it gently without crushing it, then it is likely good. If it crushes easily, then it is useless.
Thirdly, you can tell if your seeds are still good if they have a dark, thin waxy coating. Healthy ones are usually gray, black, or brown with spots or stripes. Anything contrary to this means your seed is no longer viable.
Final Thoughts On How Long Do Cannabis Seeds Last:
So how long do cannabis seeds last? Well, good quality and properly stored seeds can last for many months or years. Always store or preserve them in a dry, dark, and cool place/container. Additionally, maintain steady conditions (light, temperature, and humidity) without fluctuations.