If you have some cannabis seeds but are not ready to plant them yet, you need to know how to store them properly. Here's our complete guide. How do you store cannabis seeds so you can use them for future use? Learn how to properly care for your seeds so you can grow the best plants. Storing cannabis seeds in the right conditions allows you to preserve your favourite cannabis genetics for many years. Store your seed collection safely!
How to Properly Store and Preserve Cannabis Seeds [Explained]
If you don’t begin with great seeds, you can forget about producing a harvest of high-quality marijuana. A lot of growers seem to forget one simple fact: Your seeds are alive! Although cannabis seeds are fairly durable, improper storage can ruin them. If you’re paying $10-$20 a seed, losing a full batch is an expensive mistake.
Before your marijuana seeds germinate, they are in a similar state to animals when they hibernate. Like all living organisms, your seeds can die if you don’t take care of them correctly. The good news is that cannabis seeds can last for five years after harvest with proper storage.
In this guide, we outline how to store and preserve your cannabis seeds. We focus on the following:
- Insects & Pests
- Germinating old seeds
EDITOR’S CHOICE – Homegrown CannabisCo
Homegrown CannabisCo are the masters when it comes to seeds. Offering a massive variety of cannabis seeds that are well categorized, not only does this company create a resource for superb quality options including feminized seeds, it also provides extensive growing information for those looking for some support along their journey.
Keeping Light Away from Your Marijuana Seeds
You must keep your seeds in a location that is cool, dark, and dry. It is best if you keep the seeds in their original packaging. When they are exposed to temperature changes or light, cannabis seeds begin using their store of nutrients. This is a disaster because they ultimately won’t have the nutrients to germinate.
When they are exposed to temperature changes or light, cannabis seeds begin using their store of nutrients.
Make sure your seeds remain away from light, as it can directly trigger germination.
What’s the Right Storage Temperature?
The best temperature to store your cannabis seeds at is between 43- and 47-degrees Fahrenheit. The lower the temperature, the less likely your seed is to germinate unexpectedly. Experienced growers tend to have special refrigerators to store their seeds. Ideally, your fridge is a no-frost model. If you can place the seeds in the fruit and vegetable section, that is even better.
Another option is to freeze the cannabis seeds. If you go down this route, please ensure that you vacuum pack them first. Then put them in a dark container. Also, it would help if you germinated these seeds immediately once they come out of the freezer. Don’t allow them to thaw first.
What About Humidity?
Here is a quick overview of what will likely happen to cannabis seeds at different humidity levels:
Your cannabis seeds need a certain level of moisture for germination. If the humidity level gets too high, your seeds will rot in storage. An extremely low level of humidity of around 8-10% is suitable only for long-term storage. If it drops below 8%, you offer any insects present in the seeds the chance to become active and start reproducing.
The Right Storage Options for Your Cannabis Seeds
You now understand that you must store the seeds away from direct light. We have also outlined the need for relatively low humidity and a refrigerator-level temperature. Different options are available depending on how long you intend to store the seeds.
If you only require short-term storage, a dark drawer or cupboard is sufficient. The most important thing, regardless of the duration of storage, is to avoid temperature and humidity fluctuations. Rapid variations in temperature, in particular, can destroy your seeds. If you live in a location with warm daytime temperatures and cold nights, avoid outside storage.
For short-term storage, place the seeds in a container with desiccant. Seal it, and place it in a cool, dark place.
Once you enter medium-term storage (a few months), it is time to use an airtight container. Examples include a mason jar or Ziploc bag. Place this sealed container in the fridge. Remember that opening your fridge can cause significant temperature fluctuations. As a result, it is ideal if you have a second fridge that is seldom used.
Also, you should note that modern fridges have low humidity levels. If the humidity is too low, your seeds will begin using up nutrients.
If you want to store your seeds for at least six months, use a vacuum-sealed container. You can achieve this effect by removing all the air from a Ziploc bag. There are also special vacuum-sealed containers available online. Put the sealed bag in a dark container and put it in the fridge.
You also have the option of placing the seeds in the freezer. Remember, though; you need to germinate them immediately upon removal.
A Note on Insects & Pests
Imagine paying $100+ for seeds, going to the trouble of storing them, only to find that insects ruin them. Unfortunately, all you need is one insect in a container to destroy all of your seeds. The first consideration is to avoid exposure to ultra-low humidity. However, for long-term storage, this is precisely what you are supposed to do!
One option is to spread diatomaceous earth (D.E) where you store them. This is a type of sand that has a fossilized algae base. Crucially, for our purposes, it serves as an excellent natural insecticide. Unfortunately, you shouldn’t use D.E if you plan to store your seeds in a fridge with other food.
Imagine paying $100+ for seeds, going to the trouble of storing them, only to find that insects ruin them.
It would help if you also stored your seeds as high above the ground as possible. This reduces the possibility of a pest like a rodent coming in and feasting on the seeds.
Insects and pests also thrive in dirty storage areas. As a result, you must ensure the storage area remains clean. Otherwise, you won’t just attract pests to your seeds; microbes will form and damage the seeds. Do you want to consume marijuana from contaminated seeds?
You can ‘test’ your seeds once you have removed them from storage. Place them in water. If they sink, they should be fine. However, if they float, it is more likely that they are bad seeds. You can still try to germinate, but there is a greater risk of producing poor-quality cannabis, or else the seeds fail to sprout. You can keep floaters in water for approximately 72 hours to see if they sprout a tail.
If you have old seeds not stored in ideal conditions, there are still a few ways to germinate them.
- Remove the hard ridge with a sharp knife.
- Soak the seeds in carbonated water with germination booster, fulvic acid, or hydrogen peroxide. Use room temperature water, and perform this pre-soak for at least 12 hours in a dark area.
- Scratch the tough outer shell with sandpaper. Believe it or not, this process could help warmth and moisture get inside. This process is called ‘scarring’ and should happen before you soak the seeds.
- Make a small cut into the shell as a last-ditch attempt to get it to sprout.
Final Thoughts on Storing and Preserving Cannabis Seeds
If you purchase marijuana seeds and intend to use them almost immediately, you should have no issues. Even so, it is probably best to keep them away from direct light. In the short-term, a dark cupboard is sufficient as long as the temperature and humidity are reasonable.
Once the goal is to store cannabis seeds for months rather than days or weeks, everything changes. You need an airtight container, which you should store in a fridge. Include a vacuum-sealed container if you plan to store the seeds for several months or longer.
When storing cannabis seeds, you must ensure they are not exposed to germination conditions. This means keeping them away from direct light. Also, store in 20-30% humidity (8-10% for long-term storage) and a cool temperature. Keep the environment clean to avoid pests, and consider the tips above for germinating old seeds.
How to store cannabis seeds
Want to know the best way to grow the best marijuana? Start with great seeds. But once you find the perfect strain, how do you store seeds so that you can use them for future plants? It’s not that hard; actually, you just need to keep them cold, dark, and dry. However, there are few other things that you could do to preserve your precious seeds – keep reading to learn more.
A guide to storing marijuana seeds
If you plan to grow marijuana for fun or profit, you’ll need to know how to store your seeds.
Why is storing cannabis seeds important?
Those seeds are directly related to the quality of your plants. If they are not stored correctly, when you do get around to planting them, they will not germinate. On the other hand, if you store them the right way, they are good to go indefinitely.
Some growers keep seeds for years. However, it’s common to leave a few seeds in storage for less than a year, especially when there are limits around how much you can grow at one time. There’s no reason why those extra seeds should go to waste, simply learn how to store them correctly.
Download my free Grow Bible to learn more about storing your seeds.
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- Avoid common grow mistakes
Use the right storage container
When storing cannabis seeds, the first thing to think about is your container. Do not use just any random container that you come across. The ideal container should be made of one material.
Avoid containers with a mixture of materials. An example of this would be a plastic container with a metal lid or a glass container with a plastic cover. Containers made from more than one material react differently to temperature and other changes, and this can create room for undesirable conditions to reach your stored cannabis seeds. For instance, the metal lid on a glass jar will expand at a different rate when the temperature rises, and this may allow some moisture to enter the container.
Many people suggest using plastic containers for long-term storage when asked how to store marijuana seeds, but that isn’t a great idea either. Plastic has tiny (microscopic) pores that can let air infiltrate the container and damage your seeds. If you want your seeds to last, don’t store them in a plastic container. Glass is a much better solution.
Label the containers
Chances are you are storing more than one strain of cannabis seeds. Even if you are storing just one variety of seeds, you must label the container. Otherwise, if you store the seeds for years, you may forget which strain they are and that they are even marijuana seeds!
Keep light out
This part is simple; germination needs light. If you do not want your seeds to sprout, keep the light out. That’s why the most immediate answer to “how to store cannabis seeds” is “keep the environment light free.”
Want an easy way to keep light out?
Try using an opaque container. If the glass jars you used aren’t opaque, then place your seeds in something opaque, such as a black plastic wrap, then put that in the glass jar. Again, keep in mind, plastic is not the best for long term (years), but if you are purchasing at the end of one grow season in preparation for the next, it should work just fine.
You can also place your cannabis seeds in a fridge that doesn’t get opened much or another dark location.
Keep the temperature constant
Another thing that you need to think about when storing cannabis seeds is to maintain a stable temperature. Try and keep the seeds around 40° Fahrenheit. You do not want them to freeze.
Many people do this by keeping their seeds in a fridge or freezer. (Again, do not allow the seeds to freeze.) The most critical thing is keeping that temperature constant. Your marijuana seeds can deteriorate when the temperature fluctuates.
Keep moisture out
Moisture is the other condition that is required for germination, so you’ll need to keep your seeds dry as well. Depending on how much moisture your marijuana seeds are exposed to, they could either germinate or even rot while in storage.
For the best results, keep moisture levels between 5% and 9%. An airtight, sealed container is a great way to do this. You could also add something to help absorb any moisture, such as silica packets or even uncooked rice.
If you decide to use one of these methods, make sure you use something food-grade. Remember, this material will be sitting in storage next to your seeds. It’s also a good idea to use some sort of barrier, such as some cotton wool, between your moisture-absorbing packs and the marijuana seeds. This will leave the seeds undisturbed while the moisture problems are addressed.
Keep the storage environment clean
How to store marijuana seeds properly also means keeping the storage environment clean. If you’re not careful, pests can quickly destroy your cannabis seeds if they access the storage container and its contents.
A clean environment also keeps other contaminants, such as microbes, from compromising the quality of your seeds. After all, you will eventually plant those seeds, and you don’t want to consume cannabis grown from contaminated seeds.
Nature-designed seeds to last until the ideal germination environment occurs. Therefore, if you follow these storage tips and prevent that environment from happening, you could store cannabis seeds indefinitely.
Does it need to be perfect?
No. If you only need to store cannabis seeds for a few months, you don’t need to be that strict. However, if you’d like to keep your seeds for years, plan ahead and take the necessary precautions, and you’ll be delighted that you did.
Ready to start finding the best seeds for growing your own marijuana? Explore high-quality weed seeds in my shop.
How to store cannabis seeds the right way
Storing cannabis seeds under the correct conditions allows you to preserve your favourite cannabis genetics for many years. With the right conditions you can keep the best part of your cannabis seed collection viable for a decade or more. But get the conditions wrong and the germination rates on your best-loved feminised seeds and autoflower seeds will suffer. If you are a cannabis seed connoisseur that spends time, cash and love building a collection of the best cannabis genetics then it makes sense to learn more about storing your cannabis seeds under ideal long term conditions.
Did you know cannabis seeds are living organisms?
When preserving cannabis seeds, it’s worth remembering that seeds are technically classified as living organisms. That’s because they have an embryo which is capable of being germinated and growing into a new plant. Just like any other seed, environmental conditions for storing cannabis seeds can be fine tuned to maximise seed germination rates. But provide the wrong conditions for storing cannabis seeds and your seed germination rates will decrease rapidly. Storing cannabis seeds till germination under ideal conditions is the best way to maximise germination rates.
Key factors to watch when storing cannabis seeds
When storing cannabis seeds there are three main issues which will reduce the germination rates (or the ‘viability’) of your cannabis seeds. These are light, heat and humidity. Each of these factors will reduce the germination rates of your autoflower seeds/feminised seeds. Conversely, if you can minimise and correctly control heat, light and humidity then you will extend the lifetime of your cannabis seed collection.
Inside your cannabis seeds are delicate embryonic tissues which store the genetic code. This, in turn, defines the type of cannabis you will eventually grow. When storing cannabis seeds long term, keeping the seeds away from bright light is important – don’t store them in your grow room! A sealable, light proof container is ideal.
The shell of the cannabis seed does help to protect the embryo from light. But remember, in nature, cannabis seeds were normally dropped from the plant onto the soil in autumn/fall. There they would remain under a light covering of soil until they germinated the following spring. Cannabis seeds were never designed to cope with intense light levels. Storing cannabis seeds in the fridge, in a dark humidity proof container is a good way to maintain maximum seed germination rates.
Dutch Passion cannabis seeds can be stored simply be re-sealing the seed packet with tape and placing it inside the seed tin or a container. Storing cannabis seeds in eppendorf tubes (black or amber) in the fridge is a popular technique. Eppendorf tubes are small plastic tubes normally used for storing liquids, but they are often used for cannabis seed storage too.
When storing cannabis seeds, humidity levels are an important factor. In order to germinate cannabis seeds, moist humid conditions are used. So it makes sense to use low humidity conditions for cannabis seed storage. You certainly don’t want to store your seeds anywhere where moisture droplets, which will soften the shell. Water/moisture is a very effective way to soften the hard, rigid shell of the cannabis seed. This allows the tap root to emerge.
When storing cannabis seeds for the long term, the actual water content inside the seed will be around 10%. Storing cannabis seeds in the refrigerator is an easy way to maintain the low humidity levels that suit long term seed viability. Just make sure that your seeds are stored in a dark, dry container without any condensation near the seeds and you should be able to store cannabis seeds in the fridge for perhaps 5 years or more and still have good germination rates.
It’s not necessary to measure humidity levels in your fridge. Just ensure your seeds are in a sealed dry and dark container inside your fridge and they should last many years.
If you have produced your own cannabis seeds you may be aware that when they are very fresh, straight off the plant, they may even be a little too fresh to germinate. That’s why some believe in storing and maturing cannabis seeds for a short period at room temperature. This allows moisture content of the seed to drop enough for the seeds to become more viable. How long to let seeds dry before storing? A couple of months at room temperature should be sufficient.
|Humidity levels||Effects on cannabis seeds|
|75% to 100%||Humidity is too high, causing seeds to have excessively high internal moisture content which decreases long term germination viability.|
|25% to 75%||Good for cannabis seed storage, especially at low temperatures in sealed/dark containers.|
|0% to 25%||Too dry, seeds may desiccate (dry out excessively) especially if they were not in a sealed humidity proof bag/container.|
Storing cannabis seeds at low humidity levels in a dark place is a great way to maintain good germination rates. But one of the best ways for preserving cannabis seeds is to use low temperatures. At low temperatures cannabis seed life is greatly extended. This is because the delicate living plant tissue inside the seed can survive for much longer periods at cool temperatures which slow down the cellular biochemistry. It’s the same reason that food lasts longer in the fridge than it would at room temperature.
What is the ideal storage temperature for storing seeds? Most people use temperatures of around 4ºC (39ºF). But 4ºC isn’t a magic number. If you can ‘only’ store your cannabis seeds at e.g. 10ºC the seeds will last longer than they would stored at 20ºC. Storing cannabis seeds at 4ºC will allow longer seed storage than 10ºC.
Storing cannabis seeds in the freezer (-15 to -20ºC) is also possible and this allows even better seed storage. However this does come with some risks. When stored at freezer temperatures you can expect cannabis seeds to remain viable for decades. The very low temperatures effectively allow the seed embryo to survive for long periods.
Cannabis seed companies such as Dutch Passion store their archived seed collection (1970’s & 1980’s) in the freezer. This allows long term storage. However, it also comes with certain risks. In the freezer, the delicate frozen tissues in the seed embryo can shatter if the seeds are mishandled or shaken. That’s why the freezer is only recommended for those placing seeds into very long term storage. For most home growers, the fridge (4ºC) is a great place for storing cannabis seeds.
So what are the best ways to store your cannabis seeds?
What is the optimal temperature for storing seeds? For most people, temperatures around 4ºC (in the fridge) are perfect. If the autoflower seeds/feminised seeds are in a sealed lightproof container they are automatically at a low humidity and in a dark place.
Don’t worry too much about keeping your seeds in a fridge at all times. Remember that even without a fridge, a pack of seeds stored in a draw for a couple of years should still show good germination rates. Avoid storing your seeds in places with high temperatures or intense light, such as a window ledge or your grow room.
If storing cannabis seeds in a sealed plastic bag in the fridge remember that they are easy to accidentally crush if something is placed on top of them. A small box or plastic container can prevent that.
Should I date my seeds when storing them?
It’s probably not necessary for most people but it could be a useful guide for later germination.
How long can you preserve cannabis seeds?
In the freezer you can store cannabis seeds for decades. In the fridge, you should see good germination rates (50% or more) even after 5+ years. Without using the fridge, germination rates start to decrease earlier and faster.
If you usually germinate your cannabis seeds within a few weeks/months of purchase you may not need to worry too much about how to store them.
When cannabis seeds are supplied from the seed supplier, germination rates should be 90% or higher if you are buying from a proven supplier. Even after 5 years in the fridge you should still expect the majority of your cannabis seeds to germinate.
This is good news for those growers that have found the ideal cannabis seeds for their needs and want to ensure a viable seed collection of their favourite cannabis genetics for many years to come.
Drying, storing and maturing seeds from plants
Although not many growers can be bothered with the hassle of producing their own cannabis seeds, if you do attempt to produce seeds it’s important to know about maturing them.
When drying and storing and maturing cannabis seeds one of the main tips is to allow the fresh seeds time to rest before germinating. Fresh seeds haven’t had the natural time period required to allow them to reach maximum germination rates.
Typically seeds of various plants store better, and germinate faster when they have dried a little after the seeds have been collected. After a month or two in ambient conditions, the seeds have matured and should show higher germination rates.
What size mylar bags to use for storing marijuana seeds?
Size really doesn’t matter! Just ensure your seeds are sealed, safe from light/moisture and stored at low temperatures.
What if you found an old undated bag of seeds?
Whether you are preserving seeds of F1 landrace cannabis genetics or any other type of cannabis seeds your best chances of storing them is at low temperatures in dry and dark conditions. Many growers collect extensive (and expensive!) cannabis seed collections.
Dating each seed packet is a good idea, although it won’t improve germination rates it will give you an idea of the age of the seeds. Even after 10 years in a fridge at 4ºC you can still expect to see a some of your seeds germinate, assuming they original seed quality was high.
If your cannabis seeds are really old, some growers may suggest a few unusual tips to increases germination. Dutch Passion can’t really recommend these techniques, they simply carry too much chance of damaging the seed. These techniques include gently sandpapering the outer layer of the seed shell, perhaps including the ridge down the side. The logic here is that particularly old/hard seed shells need assistance to open.
Dutch Passion prefer to stick to proven, established seed germination techniques that should work well for most people. The best way to germinate cannabis seeds is to do so between a couple of lightly moistened cotton pads for a couple of days.