What Is The Best Way To Store Cannabis Seeds?

Adam Parsons

Cannabis Journalist & Staff Writer at Zamnesia

Adam Parsons

Last updated: February 18, 2020

After the hard work of germinating your seeds, it may be tempting to just toss your leftover beans in a bag for next time. However, you may be in for a rude awakening when it comes time to germinate your next batch. If stored improperly, cannabis seeds may no longer be suitable for planting.

Properly storing your seeds is crucial to ensuring the health and success of your next crop. Keep reading to find out how to properly store cannabis seeds so they last as long as possible.

WHY IS PROPER CANNABIS SEED STORAGE IMPORTANT?

Many growers eventually find themselves in situations where, for one reason or another, they are required to store cannabis seeds. In regions where cannabis is illegal, growers will inevitably find themselves stockpiling seeds. And even in regions where it is legal, large-scale growers typically buy seeds in bulk, making some storage necessary. By properly storing cannabis seeds, growers are looking out for the well-being of their future crops.

HOW LONG CAN CANNABIS SEEDS ACTUALLY BE STORED FOR?

Generally speaking, cannabis seeds can be safely stored for anywhere between 1–2 years, especially if they are properly stored in a cool, dark place. Depending on conditions, they can even last up to 5 years.

In theory, there is no hard limit or expiry date on cannabis seeds. When it comes to germination, the fresher the seeds, the greater your chances of success. Ideally, seeds should be planted within a few months of being harvested. However, even seeds that have been sitting around for years can still be successfully germinated. Just remember, the longer a seed has been stored, the lower its germination rate.

Additionally, seeds that have been improperly stored will require longer to germinate. While healthy seeds normally take between 48–72 hours, improperly stored ones may require as long as 5–7 days.

FACTORS TO CONSIDER WHEN STORING CANNABIS SEEDS

Growers are usually advised to store their leftover seeds in a cool, dark, dry place. But if we’re getting down to specifics, there are actually several environmental factors that can impact the quality of your seeds.

1. HUMIDITY

The humidity and temperature of your storage environment are perhaps the most important factors. Cannabis seeds will absorb moisture from particularly humid environments and will dry out in particularly dry ones.

To avoid any potential damage, a relative humidity level of between 20–30% is advised. A humidity level higher than 40% may actually trigger germination, whereas levels below 8% may give any insects present the opportunity to become active and reproduce. For long-term storage, lower humidity levels of roughly 8–10% are believed to be more appropriate.

2. TEMPERATURE

The ideal temperature for storing cannabis seeds is between 6–8℃. It is believed that the lower the temperature, the slower their vitality and ability to germinate decreases. For this reason, many large-scale growers choose to keep their seeds in a refrigerator specifically set to this temperature range. If the humidity level is appropriate, you may even be able to store them in a cool, dark corner of the fridge in your own kitchen.

3. LIGHT

Light should be avoided because it directly triggers germination. If exposed to light, seeds can lose much of their germination power later on. Many seedbanks elect to protect their seeds by placing them in opaque metal boxes.

4. OXYGEN

While not as important as the other factors, restricting your seed's access to oxygen is also a good idea. Doing so can reduce or prevent seed respiration, which, in turn, can prevent premature germination.

5. FLUCTUATIONS

Not only must you provide ideal environmental conditions for your seeds, you must also maintain them. As such, it is never advisable to open your seed container for any reason other than to plant your seeds. Apart from potentially exposing them to threats such as pests and bacteria, fluctuations in temperature or humidity can also be detrimental to the health and longevity of your seeds in general.

STORAGE CONTAINERS AND HUMIDITY CONTROL

Sealing your seed bags and containers is crucial to protecting your seeds from the elements. If your seeds came from a seedbank that vacuum-seals their seeds with silica packs, it may be OK to just store your leftover seeds like that (just make sure to protect them from light). However, if your seeds are scattered, and if you insist on storing them in bags, it may be a good idea to invest in a vacuum-sealer.

If you choose to store them in containers, make sure that they are truly airtight and heat-proof. Most plastic containers are not suitable as their lids are not airtight. Moreover, plastic containers provide questionable protection against water molecules and UV rays. As such, plastic should only be relied upon for short-term storage.

Ideally, you should stick to glass containers whenever possible. Glass containers are excellent for both short-term and long-term seed and bud storage. Just don’t forget to cover them up so as to protect your seeds from light.

Additionally, don’t forget to include a desiccant in your seed container. A desiccant will work to maintain ideal humidity levels for your seeds. It will also absorb any excess ethylene that is naturally produced during the ageing process, thus extending the life of your seeds. Silica gel packs are recommended because they are reusable. However, natural desiccants like rice can also work really well, even if they have to be regularly replaced.

METHODS FOR STORING CANNABIS SEEDS

For short-term storage, any airtight, light-proof container should do the job. If you are planning on using the seeds sooner rather than later, then storing them at room temperature is likely good enough. Simply load your container up with seeds and desiccant, seal it, and tuck it away in a dark, cool place where it will be protected from light and fluctuations in temperature and humidity. Some examples of common storage spots include the bottom of your closet or the back of a kitchen cupboard. This should be good enough to maintain the integrity of your seeds for a few months.

If you are planning on storing your seeds for longer than this, you should consider a refrigerator. Refrigerators are great for keeping your seeds at the low temperatures they require. Moreover, most of the time, fridges are also pretty dark and dry.

However, humidity tends to fluctuate inside a fridge, so it's recommended that you include desiccant in your container. It is also recommended that you store your seed container toward the back of the fridge, where the least moisture is present.

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Additionally, you should make sure to only store your seeds in “no-frost” fridges that can protect them from frost damage. Storing them inside of your vegetable crisper can be a good way to achieve this. Ideally, you should store your seeds in a vacuum-sealed, heat-proof container for maximum protection from the elements.

Freezing your seeds for long-term storage is also a possibility. However, it is believed that doing so may actually damage your seeds rather than protect them. Some growers even believe that freezing damages the living cells inside of cannabis seeds. Special laboratory equipment can be used to carefully lower the temperature of the seeds in order to prepare them for long-term freezing; however, most growers lack the necessary equipment to execute this process correctly. As such, while freezing may be an option for some growers, it really isn’t for most.

OTHER TIPS AND CONSIDERATIONS

When handling several different kinds of seeds, it's important to label everything properly for future use. It may seem obvious, but it can be easier than you think to get your seeds mixed up, especially if you are handling a variety of strains.

Furthermore, before sealing and labelling your seed containers, you should carefully check them for pests of any kind. Just one insect could potentially damage an entire batch of seeds. Make sure to tightly seal seed containers to make them impenetrable to any wandering bugs or pests.

Sealing them tightly will also prevent them from accidentally opening should they fall over. And remember, it is never advisable to open a sealed seed container until it is time to plant them.