Improper storage of seeds will cause crop failure before the first step is even reached. Cannabis seeds are living organisms and the state of cannabis seeds before germination is similar to a hibernating animal, which means the seeds could die if you don’t treat them carefully! So how to store cannabis seeds?
Luckily, it’s not terribly difficult to store seeds. You only need to keep them in a dark, cool, and dry environment.
Ideal conditions for cannabis seeds
Light
Keep your seeds away from direct or indirect light since they will germinate if they are exposed to light—especially sunlight. Light can even stimulate seeds to germinate, even if other germination conditions are not met. When this happens, they will exhaust all of the stored nutrients needed to survive, thus the nutrients will run out and won’t support germination when you plant them. In nature, the seeds fall into soil and are covered by soil, this helps to keep them away from light.
Temperature
Temperature is always an important factor that can’t be ignored when it comes to planting, this includes storage temperature. The ideal temperature for storing seeds is between 42° and 46° F. Some growers think the cooler the better, so they will store seeds at a lower temperature (-15 to -20ºC).
While the thought is that this will preserve seeds for longer, this also comes with some risks. Tissues within the seeds are already extremely fragile and adding cold to their stresses can destroy the internal structure of the plant. A final note on temperature, be sure to keep the temperature constant—if it fluctuates too frequently you could trigger growth.
Humidity
Humidity is as important as temperature. If the humidity level is too high it will cause the seeds to germinate or even rot (as they will absorb water from the air and mold will develop). So should humidity levels be at 0% in storage? Not really. The ideal humidity level for seed storage is between 8% and 10%.
- If humidity is below 8%, insects and other pests can be attracted and will damage or consume your seeds.
- If the humidity is over 10%, the seeds will breed fungi, which will also harm the seeds.
- If you just want to store the seeds for a short term (no more than several months), humidity levels between 20%-30% will be fine.
- A humidity level between 40%-60% is an ideal range for germination, so at this level, you will encourage your seeds to attempt to grow, which is not ideal.
- And what if the humidity is over 60%? The risk of death increases with the rise of moisture. Once it reaches above 60%, the seeds may die within 12 hours.
Keep a balanced humidity level. To do this, you can store the seeds in a sealed container and put some desiccant in the container. Silica gel and rice are common desiccants that are used to preserve seeds.
Choose the right container for your seeds
Whichever container you choose, be sure it can be sealed. A sealed container will help you prevent unwanted oxygen and pests from damaging seeds.
Mason jars
I recommend using mason jars because they have a great seal, especially if you are planning to save your seed for several years, Mason jars are a great choice. Desiccants can be added to keep humidity stable. One drawback of mason jars is they are transparent, so you need to cover them with something opaque and put them in a dark place.
Envelopes
If you only want to store seeds for a couple of days or weeks (a short term means the temperature is stable), you can use an envelope since they prevent light from reaching seeds. The only thing you need to do is to keep the envelopes in a dark, cool environment. What’s more, you can record some important notes on the envelopes, such as the date of storage time, the type of seeds and so on. Of course envelopes won’t work during the rainy period because they may gather moisture.
Some growers store seeds in envelopes and then put the envelopes in a mason jar, combining the advantage of envelopes with the advantage of mason jars.
How long can cannabis seeds be stored?
Cannabis seeds can be stored for quite a long time if they are properly preserved. When stored in ideal conditions—cool, dark, and dry—they can last up to 5 years or even longer without significant loss of viability.
Short Term Seed Storage
Research published in the Journal of Forensic Sciences in 2005 conducted a study which found that when stored at room temperature (approximately 20-25°C or 68-77°F) and low humidity, cannabis seeds retained high viability for up to two years. However, when stored under refrigeration (4°C or 39°F) and low humidity, the viability of the seeds was maintained for up to five years.
Long Term Seed Storage
A study published in the journal “Seed Science and Technology” in 2006 assessed the effects of long-term storage on the viability of various seed types, including cannabis seeds. In this study, seeds were stored under controlled conditions (-18°C or 0°F) for up to 50 years. While the study did not specifically focus on cannabis seeds, it demonstrated that under optimal storage conditions (low temperature and low humidity), many types of seeds, including those of similar composition to cannabis seeds, can remain viable for several decades.
Where should I store cannabis seeds?
You need to store cannabis seeds in a dark, cool, and dry environment, and the environment should be stable. A fridge could be a potentially good choice, however, the fridge shouldn’t be opened frequently. Every time you open the fridge, the temperature fluctuates and so does the humidity. Therefore, some growers prepare two fridges, the first one is for storing seeds, and the second one is for daily use.
How do I know if my seeds are properly stored?
Before you begin germinating, place your seeds in water—if they sink to the bottom they have not been stored properly. If they float for a while and then sink, they have been stored well.
How do you store your seeds? How do they go? Feel free to message our Instagram or Facebook about your experience storing your seeds, we’d love to know your tricks!
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Vee is an indoor cultivation expert specializing in tropical plants and cannabis cultivation. With extensive experience in various indoor growing setups, she excels in optimizing growth environments to maximize plant health and yield. Through hands-on experience with a variety of cultivation equipment, Vee has developed a deep understanding of indoor growing techniques. Passionate about sharing her knowledge, she empowers enthusiasts through articles, workshops, and online forums. Vee is dedicated to pushing the boundaries of indoor cultivation, whether assisting commercial operations or hobbyists, with practical and effective strategies.
