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How Long Do Cannabis Seeds Last?

Updated July 22, 2022

If you plan on growing cannabis plants, then you should take the time to learn how long the seeds can last. You do not want to spend money on seeds and then wait too long to use them and waste your money. You also do not want to risk growing cannabis of poor quality because you waited too long to use the seeds. So, how long do cannabis seeds last and what happens if you try to grow them after this date?

Specific Numbers

Most people will find that marijuana seeds can still sprout without a problem after a few years. You can likely get them to sprout even if you store the seeds for five or six years. Many people have experienced success in growing seeds that are of this age. There are also articles from experts that indicate you can grow seeds that are 15-20 years old. There is a consensus that you can expect seeds in the fridge to last at least a decade when cared for properly.

If you have patience and are willing to waste time and resources on seeds that may not sprout, you can try to grow any seeds. There are some stories of universities germinating an ancient cannabis seed. You can also easily find people on forums who claim to have successfully grown seeds that were at least several decades old. Of course, for an old seed to successfully grow, it must have been stored in the ideal conditions, and you need some luck.

Ask the Seller

Depending on where you buy your cannabis seeds, you may be able to ask the seller how long the seeds will last. Large companies should have a reasonable idea of the lifespan of their seeds. This is less likely to be the case if you get the seed from someone you know, as they will be unlikely to provide consistent quality for the seeds.

It Depends on the Strain

It is also important to keep in mind that not all strains will last for the same amount of time. Some strains will have hardier seeds, while others will have weaker seeds. You can probably find information on the hardiness of the more common strains in forums online, but otherwise, you will have to guess and hope for the best or determine it yourself.

Ideal Storage Conditions

To preserve the life of your cannabis seeds, and have them remain viable as long as possible, store them in the proper conditions.

A Cool, Dark, Dry Place

The most important factors in deciding where to store your cannabis seeds are light, moisture, and temperature. You want to choose a spot that is cool and dark. Warmer temperatures give the seeds signals to sprout. The same is true of moisture. As such, you want to avoid moisture and heat.

Ideally, you want the relative humidity to be about 20-30 percent and the temperature to be around 6-8 degrees Celsius.

Store With Drying Gel

To ensure that the seeds do not get any moisture, consider including a pouch of silica gel or something similar inside the container. This will ensure that no moisture interferes with your seeds.

Suggested Locations

Since you want to store the cannabis seeds in a dry, cool, dark place, consider your basement or the fridge. Just make sure that whatever location you choose is free from moisture.

You Can Freeze Seeds

In cases where you know that you will not use the seeds anytime soon, then you may want to consider freezing them instead. Place the seeds in a bag and vacuum seal it so that there is no extra air. Then, put this vacuum-sealed bag inside another airtight container. Stick the entire thing in your freezer, setting the temperature to about 25 degrees Fahrenheit.

What to Know When Freezing Seeds

Freezing seeds is straightforward, but you need to keep a few things in mind. You cannot refreeze seeds. If you try to freeze them after thawing them out, the seed will almost always die. You will also need to give yourself enough time to thaw out the frozen seed before you plant it. This should take around 12 hours, but the time can vary based on the conditions you froze it in and the conditions of the room where you thaw it out.

Differences in Growing Older Seeds

If you try to grow cannabis seeds that have been stored for too long, they will struggle to sprout. You should expect them to take longer to sprout and fewer of them to successfully sprout. As more time passes, fewer seeds will germinate successfully.

There is also the fact that at a certain age, a race begins between decay and germination. The seeds will be more prone to decay as they are older, so the extended time required for germination may be too long. In this case, you will plant them and introduce the proper conditions for growth, but the seed will begin decaying before it can germinate.

The Basic Steps for Growing Old Seeds

The main difference when growing older seeds compared to new cannabis seeds is that the shells will be harder. This means that they will require longer exposure to water to penetrate the thick shell.

Germinating in a Glass

You should start by putting your seeds in a glass of water for about 24 hours. You can add several drops of hydrogen peroxide to help soften the shell. By softening the shell, you speed up the process of the water penetrating the shell.

While growing the seeds, ensure that your liquid is around 22 degrees Fahrenheit, not cold. You should also be sure to keep it away from light sources. Keep an eye on your seeds during the 24-hour soaking period. If you notice them opening up, take them out of the glass. Otherwise, the seeds may drown. After 24 hours, move the seeds to a wet paper towel.

Germinating With Wet Paper Towels

Another popular option for germinating the cannabis seeds is to use wet paper towels and some dishes. Soak a paper towel in water and place it on top of a plate. Put the cannabis seeds on top of the paper towel, making sure you space them out enough. Place another wet paper towel on top.

This method is incredibly common, but there is some debate with purists. Those purists argue that the paper towels may have chemicals like chlorine that could get in the way of germination. The benefit of using paper towels is that you cannot accidentally drown your seeds like you could with the glass of water method.

Germinating in the Soil

If you want, you can also choose to germinate your cannabis seeds right in the soil. You will need to choose soil that is well-nourished and an area with plenty of light. You can also encourage the germination by using a teaspoon of fulvic acid diluted in a liter of water to wet your location. Instead of the fulvic acid in the water, you could also use carbonated water. The CO2 from the carbonated water will encourage the liquid to get into the seed, speeding up germination

Products to Enhance Germination

For those who are concerned about the ability of their old seeds to germinate, you can buy something to help. There are enhancers and enzymes designed to encourage germination. These products should also help with the very early development of the seeds.

One of the most popular of these products is Jiffy 7. This is a compressed pill made up of dried peat. You soak it for a few minutes until it becomes soil in a small sack. This soil was developed to encourage germination thanks to its sterilization, inclusion of key nutrients, pH neutrality, and ideal structure. If you are struggling to get older seeds to germinate, this can be a good option.

How Long Germination Will Take

For normal seeds, germination takes about 48 to 72 hours. For old seeds, this will take even longer, possibly up to five or six days. In some cases, it may even take weeks.

Tips to Grow Old Seeds

In the case of seeds that you want to grow, but are too old, there are some tricks you can try to increase their chances.

Use Hydrogen Peroxide

Some people suggest using diluted hydrogen peroxide to help your older seeds grow. The key is to use a diluted solution since you do not want to expose the seeds to a highly concentrated solution. The idea is that the hydrogen peroxide will help reduce the risk of bacteria starting the decomposition process.

A Last Resort: Use Sandpaper

If all else fails and your seeds are still not germinating, you can take matters into your own hands with some sandpaper. Use it to scrape off the seed’s outer layer. This will create micro-abrasions that could give water a chance to enter. Just ensure that you create minor micro-abrasions.

To use this method, get very fine sandpaper and roll it up with the rough side facing in. Secure it in place using tape. Put your seeds inside and place your hands over the openings of your sandpaper roll. Shake it for a few minutes, and you should hopefully see results.

A Last Resort: Use a Knife

Another last resort method is to grab a knife and cut your seed transversely. Only cut the seed very lightly. As with the sandpaper, the goal is to provide an opening that will encourage the water to get into the shell so that germination can occur.

Growing Old Seeds Past Germination

Once you get your old seeds to germinate, the hardest part is done. You should handle the newly germinated cannabis plants carefully for a few days. After about a week, the plant should grow just like any other cannabis plants in your garden.

The Ideal Timeframe

With all of the information given, there is still an ideal period in which to use your cannabis seeds. You should generally try to use them within about two years and store them in the proper conditions. This means a dry, dark, and cool place in an airtight container. If you use the cannabis seeds within about two years, you are unlikely to experience germination problems due to the age of the plant. There should also be no other ill effects when growing the seeds.

Where to Get Seeds

Now that you know how long your cannabis seeds will last for, where do you get them? A quick online search will show you dozens, if not hundreds, of online retailers that sell cannabis seeds. You might be able to buy cannabis seeds at a local shop, but this is not always a given. If you have a favorite local cannabis shop, ask if they sell seeds or could they get you some through their channels. If not, consider ordering online.

No matter where you choose to get your seeds, make sure you do your research. You should buy seeds from the strain of cannabis that has the features you want, such as aroma and potency. You will also want to pay attention to whether the seeds are regular, autoflowering, or feminized, as these are all different and appeal to different types of growers.

Of course, you should also look into the reputation of the seller you buy seeds from. If you buy online, look for guarantees and a reasonably long history.


When you store them properly in a dark, cool, and dry environment, cannabis seeds should still be in peak condition after about two years. There is no set time limit as to how long cannabis seeds last. With a bit of luck and proper storage, you can successfully grow seeds that are decades old, or even older. Increase your chances of long-lasting seeds by storing them properly. If you know you will not use them soon, consider freezing the seeds so they last longer. Just remember that if your seeds get older, you may need more patience when you start the germination process.

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