How to store marijuana seeds

Storing cannabis seeds under the right conditions lets you keep your favourite strains for a long time. However, doing this incorrectly can lead to a series of issues that end in the same result: the seeds won’t germinate. Here we analyse exactly what you need to do to keep your marijuana seeds in good condition, thereby making sure that they germinate successfully even several years later.

In order to store your marijuana seeds for a long time, it’s important to remember that they are technically classified as living organisms, because they have an embryo that is capable of germinating and becoming a new plant. And, like every living organism, your seeds can die if you don’t look after them properly.

Even though they’re quite hardy, if you don’t provide them with the suitable conditions for their correct conservation, their viability will rapidly decrease. Whilst its typical for them to germinate within 48 to 72 hours, they can take as long as 6 to 7 days if they’re stored badly. Or at worst they might not even germinate at all.

There are several factors to take into consideration that can reduce the germination rate of marijuana seeds: light, heat, humidity, and oxygen levels. As a general rule though, the most important factor to keep your seeds viable for as long as possible is to avoid fluctuations in the environmental conditions.

How to store marijuana seeds?

These are the key parameters to correctly store your cannabis seeds for the maximum time possible:

1- Exposure to light

The shell plays a part in protecting the seed’s embryonic tissue from the light, which in turn helps the seed remain dormant. In nature, cannabis seeds normally fall from the plant in autumn and remain under a light layer of soil until they germinate the following spring. Therefore, they haven’t evolved to face bright light, which may trigger the chemical processes needed for germination. Storing your cannabis seeds in a dark, opaque container is a great way of keeping top germination rates for the future.

2- Humidity level

High relative humidity levels are required for the germination of cannabis seeds. Therefore, it makes sense to keep them under low humidity conditions when they’re being stored. If you’re only storing the seeds for a short time (no more than a few months), a relative humidity level between 20% and 30% will be fine. If, however, you’re going to store them for longer, then keep the humidity level between 8-10%.

A good way of making sure that the seeds remain dry is to include a desiccant in the container where they’re being stored (i.e. one of those little silica gel packs that are often included with different products). These packs also absorb any excess of ethylene that may have been generated as the seeds get older and that could also stimulate germination if not removed. You can even use a few grains of rice if you don’t have any silica packs available.

3- Temperature fluctuations

When it comes to storing cannabis seeds, the cooler the better. But only to a certain point. At low temperatures, the life of cannabis seeds is significantly prolonged because the cold temperature slows down cellular biochemistry and so the plant’s delicate living tissue can survive for much longer periods. Another option is to freeze the seeds to keep them for the long term; but if this process is not carried out properly, they can eventually get damaged.

So the ideal storage temperature ranges between 4° and 8°C. You can still store seeds at higher temperatures, but their lifespan will be reduced. Many growers stick to temperatures around 4°C. However, this still isn’t a magical number.

4- Oxygen level

Although this isn’t such a determining factor, a constant supply of fresh oxygen can lead to premature germination. To prevent this, keep your seeds in a bag or airtight container, ideally vacuum sealed, although as long as the container is tightly closed that should be enough.

What’s the best way to store cannabis seeds?

There are different options depending on how long you’re intending to keep the seeds. According to the requirements mentioned above, it’s best to keep them in a dark, cool, and dry place. These are the basic conditions you can find in a standard cooler or fridge (ideally ‘no frost’ so they’re protected from the damage that frost may cause). A piece of warning here: you can’t be opening and closing the fridge door non-stop.

This is why it’s best to have a fridge specifically dedicated to seed storage. Or at least a small cooler that you rarely open; because every time you do this, the inside experiences rather significant fluctuations in temperature and humidity levels.

If you don’t have another choice, at least place the seeds towards the back of the fridge, or, even better, in one of the fruit and veg drawers, where they’re more protected from these changes. If you place some desiccant in the container with the seeds, you’ll also be protecting them from any changes in humidity.

In case you don’t have a cooler at hand, you can always store your seeds in a cool basement. Even a normal room can work well: a seed pack stored in an airtight container in a drawer or cupboard in a dark area of the house should also offer good germination rates. But do avoid storing your seeds in bright light or in hot areas (such as a windowsill or your grow room).

If you normally germinate your cannabis seeds a few weeks or months after purchasing them, you don’t need to be so strict with how you store them. You’ll be fine as long as you keep them in a cool place, away from the light, and in their original packaging (which is already optimised for their protection); and, of course, follow your common sense regarding these storage rules. If you open a packet of seeds but you don’t sow all of them, keep the remaining seeds in an airtight container.

How long can you keep marijuana seeds?

Generally speaking, always look for proven quality seeds like the ones we offer you in our Kannabia catalogue: if you provide them with all the ideal conditions that have been described, you can keep your seeds for as long as 5 years after they’ve been produced. In addition, if you maintain decent storage conditions over time (i.e. without significant fluctuations in the environmental parameters), you can expect your seeds to still be good after one or two years.

Naturally, the longer you keep your marijuana seeds, the lower the chances of a successful germination. Storing them incorrectly also reduces the possibilities of success. So store them properly, as we have described in this article, and use them as quickly as you can, to ensure the highest possible germination rate.