First-time cannabis growers have a lot of things to learn at once, and one of them is proper seed storage. Many times you end up not using all of the seeds Weed seeds can survive in the soil for years before they germinate and grow. 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…
How Long Do Marijuana Seeds Last?
First-time cannabis growers have a lot of things to learn at once, and one of them is proper seed storage. Many times you end up not using all of the seeds that you purchased, or you decided to keep some of the seeds your own cannabis plants have produced because you want to keep the genetics going, so you want to store them safely.
So, can cannabis seeds be stored without losing their viability to germinate? How long do marijuana seeds last if stored properly? We’ll cover these questions in today’s article as well as give you some tips on how to store your seeds the right way, so let’s get started.
Do Cannabis Seeds Ever Go Bad?
Cannabis seeds are much like any other plant seed – they have a waxy outer shell that protects the embryonic material on the inside, and as long as there is no damage to the shell, the seed will remain viable for germination.
However, if stored for too long without germinating or if it’s improperly stored, the weed seed can dry out to the point where it cracks, which exposes the genetic material inside, making it unfit for germination.
Another scenario would be for the outer shell to dry out and harden to the point where moisture or air won’t be able to get in, in which case the embryonic material won’t be able to survive.
The Three Main Factors That Influence the Shelf Life of Cannabis Seeds
The shelf life of cannabis seeds can be influenced by the genetics of the cannabis strain, but this is only minor compared to how they’re stored. Quality seeds may be more resilient, but if not stored properly, their lifespan will be impacted.
To preserve your weed seeds, the goal is to keep them from germinating prematurely, and to do that, you should pay close attention to the three factors that greatly influence their shelf life.
Light is one of the propagators of germination because it signals them that it’s time to wake up and sprout. If your seeds are exposed to light, crucial chemical changes will happen within the seed, and even if it doesn’t germinate now, these changes will prevent it from germinating later because the natural process will be disrupted.
Warm temperatures also signal that it’s time for germination. And not only that, but warm temperatures can increase the moisture, and excess moisture creates a breeding ground for mold and rot. Therefore, keeping the seeds at a temperature between 42°F and 46°F is recommended.
Humidity is the third factor that influences the shelf life of weed seeds and it’s also closely related to temperature. The relative humidity is a crucial element in seed germination, but when storing seeds, you want to keep it at a minimum. Relative humidity between 20% to 30% would be best – you still want some moisture so that the seeds don’t dry out completely.
How Long Do Marijuana Seeds Last?
Most seed banks would recommend that you plant the seeds within a year, but the truth is, when stored correctly, cannabis seeds can remain viable for up to five years. In rare cases, some growers have managed to keep them for seven to ten years, but this is definitely not common. You should know that the longer they are stored, the longer it will take to germinate as they will gradually lose their viability. Old seeds definitely take longer to sprout than new ones, but they do sprout nonetheless.
How to Tell That Your Weed Seeds Are Still Viable
There are some signs you can look for to check if your weed seeds are still viable for germination.
- If the seeds have a dark color, like dark brown or grey, or even black, it means that the outer shell is intact and that they’re still good to use;
- The seeds should have a waxy coating that looks shiny because it means that it’s still able to retain moisture;
- If you can lightly and carefully squeeze the seed without it cracking immediately, it’s probably still viable;
- Healthy weed seeds don’t have any cracks or holes, so if the outer shell isn’t damaged, the seed is okay.
How to Properly Store Cannabis Seeds to Prolong Their Shelf Life
The key to storing cannabis seeds is to keep them in a stable environment without changes. Frequent changes stress the seeds and cause them to use up their nutrient reserve, which inevitably makes them useless in the end.
Store Them In a Tightly Sealed Container
Cannabis seeds need some degree of oxygen in their environment, but too much of it can also invite bacteria and parasites, and not to mention, it could dry out the seeds. Therefore, keeping them in an airtight container is the safest way to make sure they remain intact.
Keep Them Somewhere With a Low Room Temperature
As we previously said, warm temperatures will incite germination, so storing your seeds in a cool place is ideal. This could be the basement, the pantry, or a storage room – anything works as long as the place has a constant low room temperature. Pay close attention to this, especially if you live somewhere warm.
Watch the Humidity Levels
High humidity poses a danger to cannabis seeds, not only because it makes them sprout when they shouldn’t, but it can also invite mold. Therefore, storing them in a relatively dry place would be great. If you’re unable to store them somewhere dry, you can place cotton balls in the container to soak up excess moisture or even use a food-grade desiccant, like silica gel packs, or even Boveda packs, as they’re specifically designed for these purposes.
Put Them In a Dark Place
Finally, weed seeds need to be protected from light for obvious reasons. Even if you use an opaque container (which is recommended), you should still store them in a dark place. You can also use a mason jar or any kind of clear glass container, but you’ll have to make sure it’s hidden from the light.
Plastic containers and plastic bags are not recommended because they encourage excess moisture and they let air in. Use them only for short-term storage if you absolutely have to.
For Long-Term Storage, You Can Freeze the Marijuana Seeds
Cannabis seeds can stay good for a few years if you meet the conditions, but you can also freeze them for long-term storage. If you end up freezing them, it’s best that you store them in a vacuum seal and remember to keep them frozen until you decide to use them. Thawed and refrozen seeds will lose their viability, so you should avoid this.
The Takeaway – Store Them In a Dark, Cool, and Dry Place for Up to Five Years
Even though seed banks recommend that you plant weed seeds within a year after buying them, they can have a shelf life of up to five years when stored properly. If, that is, you store them in a stable environment without temperature changes, high humidity, and light. Or in other words, a cool, dark, and dry place. Storing them in an opaque airtight container is ideal, but you can also freeze them if you want to. Old seeds take longer to germinate, but as long as their shell is not damaged and they still look healthy, they should be good to use.
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How long do weed seeds survive in the soil?
CORVALLIS – Weed seeds can survive in the soil for years before they germinate and grow, according to Jed Colquhoun, weed specialist with the Oregon State University Extension Service.
Why should home gardeners care?
“If you combine the longevity of seeds in the soil with the fact that weeds such as common lambsquarters can produce over 500,000 seeds per plant, the incentive to hand weed your garden becomes much greater,” said Colquhoun.
“Prevention is the most effective form of weed control,” he said.
Here are some basics on weed seed biology:
Undisturbed weed seeds tend to persist longer than seeds subjected to periodic tillage. Weed seeds in deeply worked soil tend to last longer than seeds in shallowly worked soil. Seeds deep in the soil are “stored” below the germination zone.
Grass seeds tend to be less persistent than broadleaf weed seeds.
The number of surviving seeds of most weed species declines rapidly the first year. But thereafter the rate of weed seed decline slows. Some seeds can persist for decades.
As many as 130 million seeds per plow acre were found in a Minnesota study.
Different species of weeds have seeds that last varying numbers of years in the soil. The scientific literature provides some information about seed longevity, including:
- Brome grass seed seldom lasts more than two years.
- Annual ryegrass – up to nine years.
- Perennial ryegrass – up to three years.
- Annual bluegrass – up to about five years.
- Wild oats – three to six years, but longer in deep soil.
- Jointed goatgrass – three to five-and-a-half years.
- Barnyardgrass – up to 13 years.
- Quackgrass – up to four years.
- Common velvetgrass – 10 years or more.
- Mustards – are long lived. Seeds excavated from a monastery in Denmark were dated to be 600 years old and 11 of them germinated. More commonly, mustard seeds last for decades.
- Lambsquarters – may last up to four decades.
- Russian thistle (tumbleweed) – short lived, most live only a year.
- Wild carrot – several years.
- Curly dock – more than a decade.
- Canada thistle – more than two decades.
- Field bindweed – more than 50 years.
- Leafy spurge – at least a few years.
- Common groundsel – most die within a year.
Scientists found lotus seeds in Manchuria that germinated after over 1,000 years, said Colquhoun.
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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