Weed seeds can survive in the soil for years before they germinate and grow. Want to know how long marijuana seeds last? Keep on reading! Including tips on how to store them! If you have some extra cannabis seeds lying around, you're probably wondering how long you can expect them to last.
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 marijuana seeds last?
And how to store them
If you’ve read our previous article on why you should grow your own marijuana, you learned that growing your own weed is fun, cheaper in the long run, and a sure way to never run out of something to smoke.
If you, like yours truly here are suffering from FOMO (for the non-hipsters among us: that’s short for “Fear Of Missing Out” 😉 and subscribed to a plethora of newsletters from various seedbanks to never miss out on a solid bargain, a certain luxury problem could occur: What do you do with all these newly acquired treasures when you don’t have an immediate use for them?
While nothing lasts forever, along the way I’ve learned that, if stored properly, marijuana seeds will remain viable for quite some while. With this article, I hope to finally answer that frequently asked question: how long do marijuana seeds last?
- How long do marijuana seeds last after storing them?
- How to store marijuana seeds
- What is the best place to store your seeds?
- Where do you keep your seeds in?
- Are there disadvantages of old seeds?
- How long do marijuana seeds last? let’s recap.
How Long do marijuana seeds last after storing them?
The short answer is several years or up to 5 years, depending on the circumstances.
The fact remains, that seeds exceeding that storage period are significantly harder to germinate.
So, you’ve scored big during the annual Black Friday sale and stocked up on all your favorites but then you remember, planting is months away.
Make sure your bargain isn’t going to cost you and ensure the viability of your seeds when planting time arrives with proper seed storage. It doesn’t take much, especially if you are storing seeds short term (less than two years).
If you plan to store your seeds for longer, it requires a few more steps to protect the long-term viability of the seed. But for short-term storage, a cool, dark, and dry spot are all you need.
Mother Nature’s designed them to respond to their environment within particular heat and moisture to signal the seed when it’s time to germinate.
Which, in nature is key to the survival of the plant, but not so convenient if you don’t have the intention of using them right away.
How to Store Marijuana Seeds
Marijuana seeds are living organisms which, when correctly stored, remain dormant. All seeds need to germinate is humidity and temperatures that are favorable.
Make sure your seeds don’t prematurely sprout by storing them in a spot that doesn’t have the right humidity levels and ensure the seeds are dry before sealing them in a container
Key factors for your storage conditions environment
Moisture is an especially important factor if you are freezing or refrigerating your seeds. If seeds are too wet, they can rot in the refrigerator or crystallize and suffer frost damage in the freezer. If you store seeds in the refrigerator or freezer, place the packets in an air-tight container and ensure you’ve properly dried the seeds, to begin with. As Cannabis expert Ryan Riley explains in Ryan Riley’s Growing Elite Marijuana
Consistency is key when it comes to temperature. So, you should avoid storing seeds in a spot that isn’t climate-controlled, like a garage or shed, where temperature can fluctuate wildly, especially during summer. 6 °C or lower would be ideal in terms of temperature. Unwanted fungi and bacteria in and on the seed may otherwise build up rapidly in a moist environment. High moisture levels and high temperatures will kill cannabis seeds as quickly as an invasion of microorganisms and insects, so be careful. How long marijuana seeds last, mainly depends on each 41°F / 5°C) temperature reduction in the storage environment. The recommended temperature is at least 41°F /5°C) (yes, this is slightly warmer than regular fridges). The cooler the temperature the more slowly seed vitality declines. This rule apparently continues to apply even at temperatures below freezing. At 41 °F (5 °C)
Light is necessary for germination; over-exposure may bring seeds to come out of their dormant state and encourage them to mutate. By keeping them in the darkness you ensure that they will remain dormant (provided that you’ve also taken the other requirements into account of course).
When you meet the above-storing conditions, storing cannabis for five years while maintaining high germination rates is entirely do-able.
Riley also advises making sure to label the container/package with the strain name, quantity, and date of storage to make storing easier.
In our article How to germinate weed seeds, we will teach you various germination methods that can make even the Methuselah’s among seeds sprout.
What is the best place to store your seeds?
Cool ✔ Dark ✔ That’s two out of three requirements down. As for moisture control: Experts swear by placing the seed in a closed container along with some uncooked rice to absorb any moisture (don’t forget to replace the rice regularly). A food-grade silica bag will also do the trick nicely.
Fridge is the best option, I think is to store them in refrigerators at a temperature between 6 and 8 degrees Celsius, and with relative humidity levels between 20% and 30%. And sheltered from light, of course. This spot checks all the boxes. In regard to the best place in your refrigerator, the crisper is a good choice, as it is a little warmer than the rest of the fridge.
One of the most popular places to keep your stash. The average freezer is about -15 °F dark and has a minimum of temperature fluctuations. A word of caution though! Some seedbanks keep a large stock, so you are at risk that the seeds you purchased were frozen and have now thawed. When the seeds thaw, they attract moisture. Re-freezing them causes crystallization and causes the seeds to perish!
Where do you keep your seeds in?
The freezer resolves the temperature fluctuations issue since you open it a lot less than the fridge door. Freezing seeds does not hurt them and can greatly extend their lifespan if done properly. . If you are saving seeds from a seed packet where you didn’t use all the seeds, keep the packet and put it into a Ziploc baggie.
We’ve now determined that keeping them away from moisture in a climate-controlled environment and limit the exposure to light to a minimum will significantly prolong their shelf life. Keeping them in the Ziplock bag they came in seems like the obvious thing to do. Or is there a better way?
If you plan on only storing them for a few months, cannabis seeds should do fine in a grip seal bag, placed in a mason jar, or some other type of airtight container. For more long-term storage, a vacuum-sealed package is a much more popular option. Many seasoned growers like to add a food-grade desiccant or some uncooked rice to their package as well.
What about a metal box or vault? That’s a big no. The metal will kill the seeds.
Are there disadvantages to old seeds?
Even if you’re organized, methodical, and careful about storing seeds, older seeds could be more difficult to germinate, resulting in more fragile plants, a thinner stem, and require more care and attention as seedlings.
There are a few tips and tricks to apply in order to increase your chances of successful germination.
- Sandpaper method: Some breeders use sandpaper (see video below) for older seeds. Lightly and gently scrape off the outer layer of the seed, creating micro-abrasions that help them absorb moisture more easily and then soak for 12 hours.
- Hydrogen peroxide: Soak the seeds in a glass of water with a few drops of hydrogen peroxide, for 24 hours at a temperature of 28 °C. The hydrogen peroxide softens the shell and facilitates the water’s absorption.
How long do marijuana seeds last? Let’s recap.
Saving cannabis seeds is a widely used method for preserving unique genetic varieties that one has particularly enjoyed or that worked very well when planted.
The most important factors when storing your seeds are keeping them cool, dark, and dry. Maintaining a constant environment with little or no fluctuation is vital to ensure the stability of your stored seeds.
You should bear in mind that humidity and temperature are the two most significant agents to have a quality storage system of marijuana seeds. Indeed, marijuana seeds are susceptible to their surroundings, since they dry out easily in a dry atmosphere and absorb moisture in a humid area. In every 1% reduction in the confined moisture, the life of the cannabis seeds inside the container in also prolonged.
So, there you finally have your answer as to how long do marijuana seeds last. Properly storing your seeds takes a little more effort than one would think but I ensure you, that extra care will pay off.
What’s your preferred way of storing your seeds? I’m interested in hearing your thoughts!
Educated by one of the best breeders in the Netherlands, I chose to combine my passion for writing with the fascinating world of cannabis cultivation. What are the best strains for which occasion, what are the effects, and how to use responsibly? Let me take you on a journey.
How Long Do Marijuana Seeds Last? (Explained)
If you have some extra cannabis seeds lying around, you’re probably wondering how long you can expect them to last.
The germination rate of Marijuana seeds naturally declines over time. However, if stored correctly, your seeds can last for up to 5 years. However, to last that long, they need to be good quality and be stored in a cool, dry, and dark place.
Read on to find out how to store your seeds correctly to make them last longer.
Free Cannabis Seeds? Check out my list of the best seed bank promotions – Including FREE Seeds, discount codes, and giveaways!
How Long Do Marijuana Seeds Last?
Cannabis seeds can last for a very long time if they are stored in the correct conditions. The ideal storage temperature for cannabis seeds is between 7-10°C (45-50°F), with a humidity level of around 55%. Under these conditions, your cannabis seeds should last for many years.
However, it is worth noting that the shelf life of cannabis seeds will decrease if they are exposed to light, heat, or excessive moisture. Therefore, it is important to store your seeds in an airtight container in a cool, dark place.
If you are planning on germinating your seeds at some point in the future, it is worth testing a few to check their viability first. The best way to do this is to place the seeds in a cup of water overnight. After 24 hours, check to see if any of the seeds have sunk to the bottom of the cup. If they have, this indicates that they are still viable and should germinate successfully.
How To Tell If Your Cannabis Seeds Are Still Good
Many growers have experienced the frustration of planting cannabis seeds, only to have them fail to germinate. If you’re wondering whether your stored cannabis Seeds are still good, there are a few things you can do to test them. One simple way is to do the float test: Take a glass of distilled water and drop it in your seed. If it sinks, it’s probably still good. If it floats, it’s not going to live.
Also, give the seed a light squeeze between your fingers. Healthy cannabis seeds should be firm, with a dark brown or black coloration. If they’re pale or green, they’re not going to sprout. If they’re hard and brittle, they might be too old.
The best way to tell if your seeds are still good is to try germinating them. Plant two or three seeds in moistened soil, and wait a week or two to see if anything happens. This method isn’t foolproof (sometimes seeds just don’t want to germinate), but it’s the most reliable way to tell if your precious cannabis seeds are still alive and viable.
Will Cracked Marijuana Seeds Still Germinate?
The simple answer is yes. However, it is worth noting that the germination rate for cracked seeds is often lower than for intact seeds. In addition, the process of germinating a cracked seed can be more difficult and time-consuming. When a seed is cracked, the protective outer coat is damaged, exposing the delicate inner tissue to the elements. This makes it more susceptible to infection and less able to absorb moisture. As a result, it can take longer for a cracked seed to germinate, and the plant that emerges may be weaker than one grown from a healthy seed. Despite these challenges, it is still possible to successfully grow a plant from a cracked marijuana seed. With patience and care, you can end up with a bountiful harvest of high-quality buds.
How To Make Your Marijuana Seeds Last Longer?
Let’s take a look at some of the main ways you can make your marijuana seeds last longer.
1. Store Them Properly
You can prolong the shelf life of your marijuana seeds by storing them properly. Keep them in a cool, dark place, like a pantry or cupboard. You can also store them in the fridge, but make sure they’re in an airtight container so they don’t dry out.
If you live in a humid climate, it’s a good idea to store your seeds in the fridge or freezer to prevent them from going bad.
If you have a lot of seeds, you can also store them in a Mason jar or vacuum-sealed bag. Just make sure to label the container with the date so you know when they were stored.
A Ziplock bag works well when you want to store seeds for a short duration of around 5-6 months. Any longer than that and your seeds may start to go bad.
Put your seeds into your bag, try to remove as much air as possible and then seal it tightly. Then keep your bag in a cool and dark place.
A step further than a regular Ziplock bag, a vacuum-sealed bag will ensure that there is no air left inside your bag.
This will allow you to store your seeds for a longer period.
You will still need to ensure to keep it in a cool, dark environment.
Some seed banks deliver seeds in a vacuum-sealed package that can store them until they’re ready for planting.
Another great method for long term storage is keeping your seeds in an airtight container.
Glass containers are preferable as they are more resistant to heat and UV ray damage.
Just make sure to keep them away from light.
If you are looking to store your seeds for over a year, you can refrigerate them.
Refrigerators offer constant low temperatures and dark and moisture-free environment.
Keep your seeds at the back of your fridge so that they are away from any potential moisture or temperature changes from opening it often.
Make sure the container or bag your seeds are in is airtight and heatproof.
You will also want to make sure that your fridge is “no-frost” or has a no-frost area to shield seeds from frost damage.
Freezing marijuana seeds is a debated method.
Freezing is used by some to store their seeds for years on end.
Others say that it ends up killing seeds instead of protecting them.
Some growers even believe that freezing seeds can damage their internal cells.
Using special laboratories and equipment can allow for the careful freezing of seeds, but this is not a very cheap or accessible option for many.
Now that we have covered everything there is to know about how long marijuana seeds last and how to store them, you are all ready to begin your growing adventure. We’ve made sure to cover all our bases- from basic seed facts to how to choose the best seed bank.
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Hey, I’m James! The founder and head writer here at GreenBudGuru.com. I started this site to share my passion and knowledge of all things cannabis. I used to work as a budtender in central Amsterdam, and have over 7 years of growing experience.
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Hi, I’m James, the founder of GreenBudGuru. I started this site in 2018 to help new cannabis growers avoid the common mistakes that I made as a beginner with easy-to-follow guides. GBG is now read and trusted by over 100,000 people each month.