This obviously depends on your climate too, as there are places that have incredibly high humidity and others that are quite dry, which can directly impact how you have to store your seeds. As a general rule of thumb, we recommend keeping them in a low-humidity container, and if you live somewhere incredibly humid you might have to use specific methods to decrease humidity.
A typical feminized cannabis plant can produce an enormous amount of seeds – hundreds, depending on how well the plant takes the pollen and how meticulous the pollination process is. It also largely depends on the strain, as some strains are capable of producing much more, especially if their flowers are larger and can hold more. But how long do they last once they’ve been harvested and dried?
Taking into account the previously mentioned parameters, the best way to store your cannabis seeds for long periods of time is by vacuum sealing them and then putting them into an opaque container or bag so that no light gets to them. Keep them at a constant temperature of 6-8°. Some growers use products such as silica sachets to keep humidity down even if the outside temperature/humidity becomes drastically altered – this is a good idea if you live in more humid or hotter climates.
Seed Storage: Humidity
When working from the start you’ll first need to pollinate the flowers on a female cannabis plant and then harvest the seeds once it’s fully matured. Once you have your seeds you’ll need to dry them out before they can be stored or even germinated – they should be ready to harvest once they’ve gone a dark brown color or start showing dark stripes. Most people opt to dry their seeds by simply drying the flowers and harvesting the seeds once they’ve dried out – it makes them much easier to remove from the flowers.
However, if you’re planning on crossing your own plants and making your own seeds, you’ll need to know how to harvest, dry and store them if you’re planning on keeping them for a while before germinating them; knowing how to store cannabis seeds properly is quite an important tidbit of information if you’re a professional cannabis grower.
The temperature at which you store your seeds is one of the most important factors. If you’re going for something short-term, you just have to make sure that they’re in an area with a stable temperature – do not store them somewhere where there are going to be temperature changes.
There are many different factors that come into play when it comes to cannabis seed lifespan, and the most important is conservation. If you’ve obtained your seeds from a seed bank and they come in their own packaging, when it comes to storage you can simply leave them in their packaging in a dark, dry spot; seed banks usually recommend planting within the year.
Marijuana seeds should be kept in a cool, dark place such as a basement or in your refrigerator. They should be in an air-tight container and must stay dry. Putting a cotton ball in with the seeds before storage can help suck up any extra moisture (this is why you often see little bits of cotton in seed breeder packs).
Heat and moisture ‘signal’ to cannabis seeds that it’s time to sprout, so as long as you keep the seeds in a dry, dark environment they can remain viable for years. I have heard cases of seeds sprouting after being in storage for 5 or even 10 years. However, you will notice that older seeds take longer to germinate than fresh seeds and a few of them may not sprout at all. As time goes on, fewer and fewer of the seeds will successfully germinate.