Storing cannabis seeds properly allows you to save your favorite genotypes for years. With proper care, your cannabis seed collection can last a decade or more. Your favorite feminized and autoflower seeds won’t germinate if the conditions aren’t right. Cannabis seed collectors who spend time, money, and passion establishing a collection of the best cannabis genetics should learn more about storing cannabis seeds properly.

Did you know cannabis seeds live?

Remember that cannabis seeds are technically living organisms when preserving them. They have an embryo that can be germinated and grow into a new plant. Cannabis seeds, like any other seed, can be stored in optimal conditions to maximize germination. But keep cannabis seeds in the improper circumstances, and your germination rates will plummet. The best strategy to optimize germination rates is to store cannabis seeds under optimum conditions.

Tips for keeping cannabis seeds

When storing cannabis seeds, three key concerns will limit germination rates (or ‘viability’). These are light, heat, and humidity. Each of these conditions will reduce the germination rate of your autoflower/feminized seeds. Conversely, reducing and controlling heat, light, and humidity will lengthen the life of your cannabis seed collection.

Light Exposure

The genetic code is stored in embryonic tissues inside your cannabis seeds. This determines the type of cannabis you will cultivate. Keep cannabis seeds away from bright light while storing them long-term – don’t store them in your grow room! A lightproof, sealable container is perfect.

The seed shell does help protect the embryo from light. Remember that in nature, cannabis seeds fall from the plant into the earth in the autumn/fall. They would stay there until the following spring when they would germinate. Cannabis seeds were never meant to withstand bright light. Refrigerating cannabis seeds in the dark, humidity-proof container maximizes seed germination rates.

For storage, re-seal the seed packet with tape and place it into the seed tin or container. Keep cannabis seeds in amber or black Eppendorf tubes in the fridge. It is a plastic tube designed to store liquids, but it also holds cannabis seeds.

Humidity level

Humidity is critical while preserving cannabis seeds. Cannabis seeds require wet, humid conditions to germinate. So low humidity is ideal for cannabis seed preservation. You don’t want moisture droplets softening the shell softening your seeds. Water/moisture softens the hard, stiff surface of the cannabis seed. So the taproot can emerge.

When storing cannabis seeds for a long time, the water content will be around 10%. Refrigerating cannabis seeds helps maintain the low humidity levels required for long-term seed viability. If you keep your seeds in a dark, dry container with no condensation near them, you can store cannabis seeds in the fridge for five years or more with reasonable germination rates.

You don’t need to test your fridge’s humidity. Keep your seeds in a cool, dry place in your fridge, and they should last for years.

If you’ve ever grown your cannabis seeds, you’ll know that they’re sometimes too fresh to germinate. And that’s why some recommend storing and growing cannabis seeds at room temperature. This reduces the moisture content of the seed, making it more viable. How long does it take to dry seeds? A few months at room temperature should do.

Humidity levelsEffects on cannabis seeds
75% to 100%Too much humidity causes excessive internal moisture in seeds, reducing long-term germination potential.
25% to 75%It’s ideal for storing cannabis seeds, especially in sealed/dark containers at low temperatures.
0% to 25%Seeds can desiccate (dry out) if not sealed in a humidity-proof bag/container.

Temperature fluctuations

The best way to keep cannabis seeds germinating is to store them in low humidity and darkness. However, low temperatures are one of the best ways to preserve cannabis seeds. Cannabis seeds live much longer at low temperatures. Weak cellular biochemistry allows delicate living plant tissue inside the seed to survive much longer at cooler temperatures. So food keeps better in the fridge than at room temperature.

What is the optimal seed storage temperature? It’s common to use 4oC (39oF). But 4oC isn’t magic. The seeds will last longer if stored at 10oC than at 20oC. Seeds stored at 4oC will last longer than those stored at 10oC.

In addition to refrigerator seed storage, cannabis seeds can be stored in the freezer (-15 to -20oC). But there are risks involved. Cannabis seeds can last decades in the freezer when stored properly. This allows the seed embryo to live longer.

The 1970s and 1980s seed collections of Seed Supreme are frozen. Long-term storage is possible. But there are risks. Shaking or mishandling frozen seed embryos can shatter delicate frozen tissues. So only store seeds in the freezer for very long periods. To store cannabis seeds, most home growers keep them in the fridge (4oC).

So, how should you store your cannabis seeds?

What is the best seed storage temperature? Most people prefer 4oC (in the fridge). In a light proof container, autoflower/feminized seeds are automatically low humidity and dark.

Keep your seeds in the fridge at all times. Remember that seeds stored in a draw for a couple of years should still germinate well without a fridge. Avoid storing seeds near heat sources or bright lights, like a window ledge or grow room.

When storing cannabis seeds in a sealed plastic bag in the fridge, keep in mind that anything placed on top of them will crush them. A small box or container can help.

Should I date my seeds?

Most people don’t need it, but it can help with later germination.

How long do cannabis seeds last?

Cannabis seeds can be frozen for decades. After five years in the fridge, germination rates should be 50% or higher. Without a refrigerator, germination rates fall early and faster.

You may not need to worry about preserving cannabis seeds if you regularly germinate them within a few weeks/months.

If you buy cannabis seeds from a reputable seller, expect germination rates of 90% or greater. Even after five years in the fridge, most cannabis seeds will germinate.

In other words, growers that have identified the perfect cannabis seeds for their requirements can now preserve their seed collection for years to come.

Preserving and maturing plant seeds

Creating your cannabis seeds isn’t for everyone, but it’s crucial to know how to mature them if you do. One of the primary guidelines for drying, storing, and maturing cannabis seeds is to let them rest before germination. Fresh seeds haven’t had enough time to reach maximal germination rates.

Generally, seeds of plants retain better and germinate faster when dried after collection. By that time, the seeds have matured and should germinate more readily.

How big should transparent plastic packages be for marijuana seeds?

It doesn’t matter! Keep your seeds enclosed, away from light and moisture, and at low temperatures.

What if you found an undated seed bag?

The best way to preserve cannabis genetics seeds or any other form of cannabis seeds is to keep them cool, dry, and dark. Extensive (and expensive!) cannabis seed collections are standard.

It’s a good idea to date each seed packet, even if it doesn’t boost germination rates. If your seeds were good quality, you could anticipate some to germinate after ten years in a 4oC fridge.

If your cannabis seeds are old, some growers may propose some unique germination techniques. Seed Supreme’s methods aren’t recommended since they risk harming the seed. One way is sandpapering the seed shell’s outer covering, including the ridge down the side. The idea is that old/hard seed shells need help opening.

Seed Supreme sticks to tried-and-true seed germination methods that should work for most people. It is preferable to sprout cannabis seeds between two mildly moistened cotton pads for a few days.