When it comes to growing your own cannabis, there’s a lot to learn. You’ll pick up most of the information as you go. One of the most common questions for… cannabis seeds viability storage how long last methods containers temperature humidity expiry preservation Whether you are a cannabis fan who has just begun growing a couple of plants recreationally, or you are looking to test your green thumb for the first time, there is one question that’s going to come up at some point. Do seeds go bad? Let's find out!
How Long Do Cannabis Seeds Last?
When it comes to growing your own cannabis, there’s a lot to learn. You’ll pick up most of the information as you go. One of the most common questions for growers is “how long do cannabis seeds last?” The answer is not always clear.
Cannabis seeds will last longer if they’re stored properly out of harm’s way. If you don’t know the best way to store your seeds, read on. We’ll answer “how long do cannabis seeds last” and give you some tips for getting the most out of your seeds.
Keep in mind that there is no concrete answer for how long cannabis seeds will last. In fact, the only guarantee is that it depends on many things. Storage, the specific strain, and other factors will affect the lifespan of your seeds.
Marijuana seeds last the longest in the refrigerator
As with many things related to growing cannabis, there is some debate about the best ways to store seeds. There is also plenty of debate surrounding how long they will last in any given storage space.
Leafly says that seeds must be properly stored to prevent mold or pathogens from spoiling them. They should be stored in a cool, dark place and can be used within 16 months. If you’ll be waiting longer than 16 months, it’s best to put them in the freezer to use in the future.
However, some suggest that seeds can last for years when stored in a cool, dark place. Like we said, there is plenty of debate surrounding best practices for growing weed. If you have stored your seeds in a cool, dark place for a long time, examine them thoroughly and be cautious. Expect to lose more seeds as time goes on, though. The longer they sit in storage, the more likely it is that some won’t germinate.
So, to be on the safe side, it’s best to refrigerate or freeze your seeds for long-term storage.
If they’re not stored in a cool, dark place, and are instead stored in regular conditions, they will last significantly less time. Some sources suggest they will only last a few months in regular conditions. If you don’t plan to use your seeds in the near future, it’s best to store them somewhere cool and dark to prevent pathogens and mold.
As a general rule, try to use your cannabis seeds within the first three years of obtaining them. Five years is considered very old for seeds. The quicker you can germinate and use your seeds, the better. In fact, the longer you wait, the less likely it is that the seeds will germinate at all.
What factors affect cannabis seed longevity?
First of all, try to keep your seeds in their original packaging if possible. This will prevent them from being exposed to light or other no-nos. If they’re already out of the packaging, that’s okay. Keep them in a sealed container, in a dark, cool place. Or sealed in the refrigerator or freezer.
It’s not necessary to freeze your seeds, but some people prefer to freeze them instead of refrigerate them. If you don’t open your freezer as often as you open your fridge, it may be logical to freeze them instead. This will prevent frequent temperature changes and potential light exposure.
Additionally, too much or too little humidity and the presence of oxygen can also affect the longevity of your seeds. Keep ‘em cool. Keep ‘em dark.
And don’t forget genetics and quality. Some seeds will just fare better than others because they are higher quality and more durable.
What happens when cannabis seeds are stored improperly?
If seeds are exposed to light or rapid temperature change, this can trigger a number of events that will damage their longevity.
First, it can trigger them to use up their nutrient stores before they should be used. This means when it’s time to germinate, they won’t have enough nutrients. Exposure to high humidity can trigger fungi growth.
Here’s some more information about how humidity can affect cannabis seeds, courtesy of Royal Queen Seeds.
If the storage space has an 8-9% level of humidity, it may eventually attract pests and insects. Once it hits 12-14% humidity, it’s possible for fungi to grow inside and outside of your seeds.
When humidity levels reach higher levels, around 18-20% humidity, the seeds will begin to sweat. Once you’ve reached 20-30% humidity, it’s a good idea to store your seeds. Around 40-60% humidity will lead to germination. You don’t want this if you’re not using your seeds yet. And finally, 80-100% humidity will cause seeds to drown and wilt in less than a day.
Best practices for storing your cannabis seeds
If you don’t plan to wait a long time, you can store your seeds in a cool, dark place. However, if you want to be extra certain they will survive, refrigerate or freeze them.
When you refrigerate or freeze your seeds, you need to protect them from your regular use. You don’t want your seeds getting exposed to light and temperature changes on a regular basis because they’re in your fridge. So, store them in the device you use less often (or better, a second fridge you rarely use) to prevent frequent temperature changes.
The best way to store them in a refrigerator or freezer to keep them in a nice, airtight container. Ziplock bags are a good choice because you can squeeze most of the air out and create a tight seal over your seeds. But don’t stop at the bags. Once you’ve sealed them in a ziplock bag, you’ll need to put it inside a darker bag or container. This will prevent deterioration from light every time you use your fridge.
It is possible to expose your seeds to excess moisture if they’re improperly stored in the refrigerator or freezer. If you don’t plan to leave them for long, you can skip the fridge and store them in a dark, cool zone. But if you do use the refrigerator to store cannabis seeds and want to make sure they don’t get too much moisture, you could add a little bit of uncooked rice to their container. Some growers suggest this will absorb excess moisture and prevent the seeds from deteriorating.
As with many things cannabis and gardening, different people like to use different methods. What works for you may not be someone else’s cup of tea.
But when it comes to storing seeds, you need to be careful. It’s crucial to keep them in an environment that prevents them from getting damaged and losing their ability to germinate.
The best way to store your seeds will depend on many factors. Assess how long you plan to leave them for, the quality of the seeds, and the storage spaces you have available before deciding how to store them. And good luck!
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How Long Do Cannabis Seeds Last?
Knowing how to properly store your cannabis seeds isn’t rocket science, but to a beginner grower especially, there’s a lot to be aware of. The key factors in maintaining seeds are storage methods, light, temperature, and humidity. If this looks like a minefield, don’t panic!
In this article, we’ll walk you through the main dos and don’ts of storage – not just the hows, but also the whys – and those precious seeds will be good to grow when you’re ready.
Understanding the Key Elements of Seeds Storage
To store marijuana seeds, it’s essential to starve them of the conditions they need to develop. Failure to do this can lead to a drop in germination rate, and you could easily find yourself opening a container of useless seeds which are no longer viable.
Consider all the variables involved in plant growth, and if needs be, carry out further research to better understand how these can impact seed storage. Since most plants see winter as the time of dormancy and spring as the time of new growth, the way you store your seeds should try to emulate the critical conditions of winter, which should keep the seeds from germinating.
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Understanding Cannabis Seeds
Cannabis seeds are similar to any other type of seed used to produce plants. They’re hardy-looking things, but they have a shelf life. They’re also susceptible to environmental changes – too much fluctuation in any direction can cause them to spoil. An undesirable extreme change in temperature or humidity at the wrong time (during storage) will put paid to your seeds. Light is the other main naturally-occurring variable you should protect your marijuana seeds from.
It’s important to remember that your seeds are dormant before germination but very much alive. For this reason, it’s best to treat your cannabis seeds with a degree of care and common sense. Unless you’re about to germinate, make sure your seeds ‘sleep’ in ideal conditions.
How the Main Variables Affect your Cannabis Seeds
It’s one of the classic storage instructions on packages for all manner of products – store in a cool, dry, dark place. As mentioned above, high temperatures and moisture levels tend to cause things to spoil, especially if they contain natural ingredients.
Light, heat and moisture all signal to your seeds that it’s time to sprout, and each of these variables affects your seeds differently. Exposure to any of these elements will cause your seeds to expire unless they’re well protected.
When you store cannabis seeds, it’s essential to keep them away from light. For example, don’t be tempted to throw a handful in a baggie and keep them in your grow room. Keep your seeds in their original packaging, or transfer them to an opaque, airtight container. Something such as an envelope or a blacked-out mason jar is perfect for room-temperature storage. Keeping seeds well-shielded will prevent them from absorbing any light before your planned germination time.
The shells – those hard, waxy coatings on seeds – offer a degree of protection against light. But while cannabis plants love light, cannabis seeds do not. In nature, cannabis seeds fall from the plant towards the end of the year when daylight levels are reduced. They then sit beneath a light covering of soil until the following spring when they could naturally germinate and bloom. It helps to think about the natural cycle when storing cannabis seeds. Keep them dormant until you decide you want them to germinate.
If you want to store your cannabis seeds long-term and retain their viability, it’s imperative to keep humidity levels under control. Moist, humid conditions are key ingredients in the seed germination process. If you expose the seeds to high humidity levels too soon, they may begin to germinate on their own. You don’t want to store your seeds at too low a humidity either – that can bring a different set of problems entirely. Here’s how humidity levels can affect seed viability:
These figures are a rough guideline, as risks vary slightly depending on storage method and container type. Still, they serve as an excellent approximate rule of thumb for humidity levels. Excess moisture will soften the seed’s outer shell and cause the taproot to emerge. If you’re not actively germinating that seed, it’s spoiled.
Monitoring Humidity Levels for Cannabis Seeds
Keeping tabs on relative humidity levels is reasonably straightforward. You can pick up a humidity meter on Amazon.com, and while they can vary in terms of features and cost, there are budget humidity meters which are inexpensive and still do the job.
How to Control Humidity Levels for Cannabis Seeds
Start by choosing the storage container wisely and then the environment. Use an opaque tin, plastic container or the original packaging, so long as it’s a container that seals tightly. After that, it’s a question of choosing the right environment to ensure humidity is right for safe storage. Toss in a desiccant like a silica gel pack for extra help.
Storing Seeds Shorter-Term in a Room
If your planned storage spot is in a room that’s prone to condensation on the windows, pick another location. Condensation is a good indicator that room humidity is too high, and this will harm your seeds quickly. Choose wisely – laundry rooms or bathrooms naturally make bad spots to stash seeds due to high heat and humidity levels. A living room drawer or a dark cupboard in an area that doesn’t see too many extreme temperature fluctuations is ideal.
Opening windows and vents will help keep humidity levels nearer the sweet spot. If your storage space is prone to humidity, it may be worth investing in a dehumidifier. It’s impressive how much moisture these can pull out of the air after a few hours, so it’s good to know that some devices can decrease room humidity fast.
Storing Cannabis Seeds in the Refrigerator
This is a fairly common strategy for storing cannabis seeds. Seeds are placed in a suitable container and kept safely in the refrigerator for years, retaining great viability rates. The lower temperature of the fridge makes an ideal environment for preserving seeds, working in a similar way to storing food in your refrigerator. At low temperatures, the cellular biochemistry of the seed slows down, and the seed remains viable for years. This is why a cool place is always best for storing seeds.
Storing Cannabis Seeds in the Freezer
It’s certainly doable, but it’s arguably not necessary. Storing your cannabis seeds in the correct container in a freezer will undoubtedly extend the viability of those seeds. But is it a gamble worth taking? Sure, if you have many big projects planned and many seeds to store. In most cases, though, storing your seeds in a refrigerator is just as helpful and probably less risky. Some collectors store vintage seeds in a freezer for long-term safety, but this isn’t a necessity for most of us.
The Ideal Temperature Range for Safe Seed Storage
If storing your seeds in a cool, dry place, pop them in a drawer well away from heat sources. This quick and easy way to keep seeds stashed will ensure a good degree of viability in most cultivars. The main thing is to keep the temperature low and away from the risk of temperature changes. The lower the temperature, the longer you should effectively be able to store your seeds safely.
If storing cannabis seeds in the fridge, make sure your fridge can maintain a steady temperature of between 4°C and 6°C. This will ensure safe long-term storage. In both cases, it’s best to store seeds in a suitable container, especially if you’re storing them in a fridge. The lower temperature of the fridge demands a little more protection for your seeds. An opaque tin or container with a seal that is air and watertight is your best friend in this instance.
Not all seeds are created equal. If you’ve grown different cannabis strains from seed, you’ve probably noticed that some seeds are larger or more resilient than others. Some batches will occasionally contain failures, but most seeds should store long term without any hassle. Not every seed in a batch will necessarily respond the same way, though. In a bag of ten seeds, you might find a couple don’t germinate, and while this is annoying and unfortunate, it’s sometimes just the nature of the genetics.
Hypothetical Case Studies
Customer 1 is a hobbyist cannabis grower. He buys a couple of bags of seeds from Seedsman during a promotion, intending to plant some now and store others for later. Customer 1 can safely store his surplus seeds in the original package or transfer them to a suitable container. He can seal it and place it in a dark, dry cupboard or drawer, away from any heat source. Using this method for short-term storage, Customer 1’s cannabis seeds should easily remain viable for between three and five years.
Customer 2 is a commercial cannabis grower. She buys her cannabis seeds in bulk, but only ever has a dozen plants growing at any given time. In this situation, she can safely store her surplus seeds in an appropriate container inside a refrigerator. She sets her refrigerator to maintain a steady temperature between 4°C and 6°C. Using this storage method, Customer 2’s cannabis seeds should easily remain viable for five years or more.
Customer 3 is a well-known seed bank. They are looking to preserve certain genetics long into the future, and store those particular older seeds in a freezer. They ensure to keep seeds in the correct containers and handle them with care at every stage. Aware that the frozen tissue inside the seeds becomes delicate and at risk of shattering, they treat seeds with the utmost caution. These steps should see their seeds retain a high rate of viability for decades.
Having Quality Genetics Helps
The answer to the question, then, is seed viability is largely dependent on how you store your seeds. By knowing how long you want to keep your seeds, and storing them accordingly, you can take the proper steps to ensure they will remain viable for as long as you need them to. Remember that seeds contain living matter, and there’s always a percentage risk of failure. This is true regardless of how well you handle and store them. By buying cannabis seeds from a top-quality seed bank like Seedsman, you ensure greater quality of genetics and stack the odds of a high germination rate in your favour.
Cultivation information, and media is given for those of our clients who live in countries where cannabis cultivation is decriminalised or legal, or to those that operate within a licensed model. We encourage all readers to be aware of their local laws and to ensure they do not break them.
Do Cannabis Seeds Go Bad?
M any pot fans are starting to look into growing their own supply. After all, how hard can it be? Nature does it all the time, and it doesn’t even have any grow light options other than the sun. While you may not be producing showroom quality nugs, there’s a pride that comes with tending to your own garden and snipping buds straight off the branch. Plus, you can’t beat the price.
Plenty of online stores sell seeds so it’s pretty easy to pick your favorite strains to start. However, if it’s been a while since your seeds arrived and they’re not yet planted, you can forgive yourself for wondering if maybe you’ve waited too long. After all, how long do marijuana seeds last? Whether you are a cannabis fan who has just begun growing a couple of plants recreationally, or you are looking to test your green thumb for the first time, there is one question that’s going to come up at some point.
Do Marijuana Seeds Go Bad?
First off, marijuana seeds are the same as many other plant’s seeds. A waxy outer shell called the seed coat protects the embryonic shoot, stem, and root contained within, which are nourished by a nutrient-rich oil surrounding them. As long as the shell remains intact and the plant inside doesn’t dry out or get damaged, your seed can still grow into a cannabis plant.
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However, this shell will not last forever. Once it dries out and hardens the seed coat can crack and expose the embryonic plant to damage. Or the seed coat hardens to the point that it no longer lets in moisture. In both cases, the seed is no longer viable.
Of course, there is some debate in the cannabis community over how long do marijuana seeds last. Some growers claim that when stored in the ideal conditions, marijuana seeds can last anywhere from six months to a year after packing and still spout once placed in the soil. Other producers believe that marijuana seeds can last up to a decade if properly refrigerated in the right containers.
Most seed producers agree that on average three to six years is a maximum for viability, and every day that the seed is stored drops the chances of it germinating just a little bit.
So how long do marijuana seeds last? In general, six months is the maximum if you’re looking for a nearly 100% germination rate. After three years, you’re looking at a germination rate of around 50%.
What constitutes “ideal conditions” for cannabis seed storage also depends on the genetics of that particular plant. Some cannabis strains produce a much hardier, longer-lasting marijuana seed that can last for years and still stretch their leaves once planted. Others produce seeds that need to quickly return to the soil.
How Marijuana Seeds Are Stored
In terms of long term storage for your marijuana seeds, there are four main factors to consider:
When it comes to how long marijuana seeds last, temperature is the main factor. In nature, heat tells the seed that winter’s over and it’s time to start sprouting. If your marijuana seed’s not in the soil, this means that the plant matter inside the marijuana seed will begin to germinate and then rot.
41 degrees Fahrenheit (5 degrees Celsius) is the absolute warmest you want your storage spot to be, with the sweet spot being somewhere around 38 degrees Fahrenheit.
If you are refrigerating your marijuana seeds, they’ll last the longest in a separate unit or a spot near the back. Every time you open your fridge you are changing the temperature which can harm the seeds over time.
Humidity is also your enemy when it comes to how long your marijuana seeds will last. When a seed gets wet, it cracks open to allow the sprout and root out. This will let in rot if the seed isn’t planted. A humidity level of about 5% is the maximum you want to allow.
Much like heat and humidity, light tells that seed to wake up because it’s time to spring forth.
In order to keep your seeds from going bad, it’s best to keep them stored in a dark container in order to avoid light. photo credit
By keeping your seeds in a dark or opaque container, they’ll keep dozing long term. Light can also damage the surface of the marijuana seed, which in turn will damage what’s stored underneath, causing your marijuana seed to go bad.
Besides being dark, for your marijuana seeds to last long term, you want to expose them to as little oxygen and carbon dioxide as possible. These gasses are what growing plants breathe, as well as the pests that consume them. If you’re refrigerating or freezing your marijuana seeds, make sure your container is as airtight as possible. If you can vacuum seal them, even better.
Alternatively, if you’re planning on planting in the next few months, regular mailing envelopes will do in a pinch. They’ll keep the marijuana seeds out of the light and dry, so all you have to do is store them in a cool place. Plus, envelopes make it easy to label your strains so that you can keep them separate.
How To Tell If Your Marijuana Seeds Are Still Healthy?
What should you do if you find some old seeds and have no idea how long they were stored? Maybe past you put them in a freezer bag in the hopes of keeping your favorite strain alive, or found a couple at the bottom of a baggie that the trimmer missed.
How do you know if your marijuana seed has gone bad, or if it’s healthy and viable to grow into a plant? There are four easy ways to check if your marijuana seed is still good.
If your seeds are dark brown, black, or gray, that’s a very good sign. The shell is intact and uncompromised, which means the genetic material inside has been kept safe.
Seeds should have a dark color. If seeds are still green they are probably not ready yet. photo credit
Viable seeds should also have stripes or spots all the way around. If the seeds are white or green, they’re most likely still immature.
Check if the seed still has a waxy coating. A healthy seed should have a slight sheen to it, as though it’s been oiled. This means the seed still can retain moisture.
If the seed is still healthy, you should be able to lightly squeeze it without it crunching between your fingers. If the shell has no give and splits or splinters under light pressure, then your marijuana seed has gone bad and has no chance in the soil.
Cracks or Holes
If there are any cracks or holes anywhere on the shell, your marijuana seed’s likely gone bad and will most likely not sprout. Bacteria and other harmful lifeforms can find their way into the seed, or it will dry out.
The True Test of a Cannabis Seed
Of course, the best way to test whether your seeds will sprout is to plant them and see. If some green shoots climb their way out of the soil after a couple of days or weeks, you’ve got your answer.
Storing marijuana seeds is a great way to make sure you always have your favorite strains on hand, as well as to keep yourself stocked up on plants for the long haul. Luckily, marijuana seeds can last for years as long as you make sure your seeds are cool, dry, airtight, and out of sight. There’s no better time than now to learn a new skill, so let’s see how green your thumb can get.
How Do You Tell If a Seed is Good or Bad?
If the seed is dark with stripes or spots all the way around, has a waxy shell that doesn’t crack when you give it a light squeeze, and doesn’t have any visible cracks or holes, it’s probably still good. If there are holes in the shell, it’s dry, or especially pale, your marijuana seed’s probably gone bad.
Do Autoflower Seeds Go Bad?
All marijuana seeds can go bad, including autoflower seeds. However, by keeping your seeds at a stable 38 degrees Fahrenheit and at around 5% humidity, as well as airtight and out of the light, your seeds may last up to 5 years or more.
How do you like to store your seeds? Share your thoughts in the comments!
Paul Barach is a Seattle-based freelance writer, editor, and author with experience creating well-researched, edited web articles covering cannabis news, culture, history and science. Paul is a regular contributor to PotGuide and has also contributed to publications such as Medium.com, SlabMechanix, Litro, and The Trek. He prefers to spend his free time outdoors and most recently hiked the Pacific Crest Trail. So far he has only fallen into the La Brea Tarpits once. You can follow him on Instagram @BarachOutdoors and stay up to date professionally through his LinkedIn page.