How Long Do Cannabis Seeds Last?

Oops, you’ve ended up with too many Cannabis seeds for the season, and you need to store them for the next. Storing them improperly might affect your germination success rate next season, so how exactly do you store Cannabis seeds to keep them viable?

At Aussie Hemp Seeds, we’ve spent years helping growers like you successfully cultivate cannabis and since we’re a seed bank, storing seeds is our thing! 

In this blog post, we’ll go through how long marijuana seeds last, the best ways to store the weed seeds, and how to deal with old seeds.

How Long Do Cannabis Seeds Last: Key Takeaways

Cannabis seeds can stay viable for as long as 10 years when they are stored properly. However, since nutrients reduce over time, it’s better to use the seeds within one to two years.

The best way to store weed seeds is in a dry, airtight container. Place them in the refrigerator’s crisper drawer, as it tends to maintain a more steady temperature for higher germination rates.

Don’t open the storage containers too often.

Also, label them so you don’t lose track of your seeds.

There are many ways to confirm if your seeds have gone bad. The common way is when it becomes soft and breaks easily when you press it between your fingers.

Nothing stays the same forever, and this applies to cannabis seeds as well. They have their delicate seed tissue encased in a hard shell, and this tissue gradually and naturally decays over time. 

Introduction to Cannabis Seed Shelf Life

Germination issues are often related to the seed’s viability right from the start.

Why Seed Viability Matters

The viability of your marijuana seed can make or break the health of the plant as it develops into each stage of the growth cycle. 

If you look closely at a cannabis seed, you notice a hard outer shell. This casing protects the internal seed tissue that is fragile. 

It also prevents the embryo from drying out too much, keeping it dormant until the right conditions for germination are met. 

If you buy packs of weed seeds but only need a few to create plants for cloning, you’ll want to keep the remaining somewhere for the next couple of months (if not years) till it’s time to cultivate the next batch. 

How you store the seed will significantly affect their longevity, but there are also other things to consider.

Factors Affecting the Shelf Life of Cannabis Seeds

The shelf life clock kicks in not just when you receive them, but it starts from when the seeds are harvested, packed, and shipped to you, the buyer. 

Cannabis seed production technique 

The production technique of the seed will affect its longevity. Cannabis seeds need time to fully ripen on the plant before they are harvested.

This ripening period varies by strain and affects how long the seeds will last once purchased. 

A good practice, on the part of breeders, is to immediately move freshly harvested seeds into cold storage. 

This extends their lifespan and ‘winterises’ them, which can improve germination rates.

Quick Tip:

• At Aussie Hemp Seeds, we are a reputable seed bank trusted by Australia’s top growers. We often winterise our seeds for a few weeks at cold temperatures to enhance germination rates before selling them.

Heat Levels

Heat is the enemy of seeds, and prolonged or excessive exposure can significantly affect viability. 

A cold, dry, and dark place is the most conducive environment for ensuring seeds reach their maximum lifespan. 

Light Exposure

The more light a cannabis seed receives, the more quickly it starts to get damaged, starting from the outer shell. 

Humidity Levels

High humidity can cause seeds to rot so keep the storage area dry. 

How Long Do Marijuana Seeds Last?

How long marijuana seeds last depends greatly on the storage conditions.

Average Shelf Life of Cannabis Seeds

The average shelf life of a cannabis seed is 5 years. Under the right conditions, you can still germinate seeds that are this old.

You may have read about some growers who managed to successfully grow seeds that they kept away for close to 10 years ago. While this is not far-fetched, it’s generally easier to germinate fresh seeds than older ones. 

Meanwhile, there’s a limit to how long you can store seeds. This is an especially important aspect you want to know if you plan on preserving the seeds long-term.

How Long Should you Store your Cannabis Seeds?

How long you can keep cannabis seeds depends on how well you store them.

For instance, if you store seeds in the freezer, 50% of them may still germinate well even after being stored for over five years. 

If you don’t have access to a refrigerator and want to store the seeds in a locker or basement, then expect the germination rates to be reduced. 

We recommend that regardless of the storage conditions, it’s best to use them within a year or two.

How to Store Cannabis Seeds for Maximum Longevity

The idea of properly storing seeds is to ensure they don’t sprout prematurely and remain viable when you’re ready to plant them. 

Consider the storage condition/environment, the container or bag in which you put the seeds, and how you handle the seeds during routine checks.

Ideal Storage Conditions

To provide the best storage environment for your cannabis seeds, consider the temperature, humidity, and level of light exposure in that space.

Temperature Control

If you plan to store the seed somewhere in your garages or sheds, note that you have less control over the temperature of those environments.

Consistency in temperature is crucial for storing seeds. The ideal temperature is a maximum of 5°C (41°F) or lower, such as in the fridge. 

This is because high moisture and temperature can encourage the growth of fungi, bacteria, and insects, which are enemies of your seeds.

Humidity Levels

The Relative Humidity (RH) of the storage space needs to be between 15% and 20%, which you can achieve in a refrigerator. Note that the seeds have to be dry before you put them in this condition. 

Quick Tip: 

• Desiccants like silica gel can help you control humidity by absorbing moisture in the area where you store the seeds. Simply place it into your airtight storage containers and seal it.

Darkness and Light Protection

In addition to other storage conditions discussed above, the seeds need to be in the dark and protected from light. A basement is a good choice, and be sure to control the light exposure. 

It’s even much easier to control light exposure when you store the seeds in the fridge. Just use a dark, opaque container!

Best Containers for Storing Seeds

Seeds sold at Aussies Hemp Seeds come in packaging that is already ideal for storing seeds and keeping them fresh for as long as possible. 

If the seeds come in original packaging from a reputable seed bank, you can just store them as they are. However, here are some alternatives you can use. Remember to be sure your seeds are completely dry!

Ziploc Bag

For those leftover seeds from a packet, Ziploc bags work just fine. 

The design of a Ziploc bag provides a climate-controlled environment with minimal light exposure—exactly where marijuana seeds need to be for preservation purposes.

Airtight Containers

If you only want to store the seeds for a few months, then consider a mason jar or airtight container. These two options are common household items and will work best for short-term storage. 

A typical airtight container will have tight lids that firmly close around the container. This design can be subject to wearing out but will work perfectly well for preventing air penetration within the first couple of months of usage.

Mylar Bags

If you want to keep the seeds for a longer time, say, more than one year, then a mylar bag is a better choice. 

By using a heat sealer to seal the bag, you can keep the seeds viable for years.

Common Mistakes to Avoid in Seed Storage

As with most other things that concern cannabis cultivation, it’s easy to make mistakes. Here are some common errors and how to avoid them.

Exposure to Moisture

One common mistake is opening the container where the seeds are stored too often. 

Each time you open a container, the seeds are exposed to air and moisture, which can contaminate them. 

What To Do Instead: Only open the container when you’re about to use the seeds. Generally, it’s a bad idea to touch weed seeds too much.

Incorrect Labelling

Another mistake is ignoring the importance of labelling your containers or bags. Even if you’re just storing one container of weed seeds, you may eventually need to save another batch of seeds later on. 

Labeling will help you determine which seeds are older. It also helps you not to lose track of your seed varieties. 

What To Do Instead: Label your seeds clearly with the variety name, storage date, plans you have for the seeds and other important details. 

Quick Tip: 

• Use water-resistant ink so the labels don’t fade off.

Improper Handling

Mold is a big threat when preserving cannabis seeds, and you increase the risk of mould infestation on the seeds when you touch them too much, especially with dirty hands. 

What To Do Instead: Always use clean hands when handling seeds. Avoid touching them with anything dirty.

How to Tell if Marijuana Seeds Are Bad

Unfortunately, many growers buy weed seeds from unreliable seedbanks only to receive them and see some have already gone bad. 

Here are some signs that will help you identify good or bad seeds before buying or storing them:

Visual Signs of Degradation

It is most likely a bad, unhealthy seed if it is soft and breaks easily when you press it between your fingers. If it’s not firm to the touch, then it’s not healthy. 

Apart from feeling, you can also check the appearance of the seed. Healthy seeds are usually pale brown and have darker patches with shiny surface. 

If the seed is not fresh, you might see wrinkles, and the seed will look dry and uncharacteristically black. 

However, a visual inspection often isn’t enough. Here are some other signs. 

Conducting a Float Test

Source: Youtube

Another way to check the quality of cannabis seeds is the popular “float test.” 

• Fill a glass with water halfway to the top.
• Put your seeds in a glass of water
• Allow the seeds to sit for a few hours.

Any seed that sinks is viable and will grow into healthy plants. Seeds that float are likely not viable and should not be used. 

This is because when seed tissue starts to decompose, it releases gases that cause it to float. 

However, some good seeds might still float, so don’t rely on this test alone to decide if your seeds are good.

Germination Test for Older Seeds

Overall, the best way to check the quality of seeds is to grow them. Seeds that are not good will not sprout. 

Seeds of average quality will take a long time to germinate. The best seeds will start growing a root within 2–10 days.

Note that the duration before sprouting depends on the method of germination. In this separate guide, we’ve explained the best practices for germinating cannabis seeds.

How to Revive Older Seeds

Now that you’ve come this far in this guide, you may be wondering if old seeds can still germinate. Even if they float and look old, they might still germinate.

To help old seeds stand the best chance, you need to “revive” them. The shells of marijuana seeds become harder as they age, making it difficult for the water to get through to the tissue. 

The best way to revive older seeds is to soak them in a glass of water with a few drops of hydrogen peroxide for 24 hours. The hydrogen peroxide helps soften the shell so that water can penetrate more easily.

Make sure the water is around 22°C, and keep the container away from bright light. 

Check on the seeds closely during the 24 hours and remove them promptly if they start to open so they don’t “drown.”

Tips for Using Older Seeds Successfully

To help old seeds germinate, you can try a few methods:

• Scar the Seeds: Older seeds often have a tough outer shell. Lightly scratch the shell with sandpaper to let moisture and warmth get inside. Do this just before soaking the seeds.
• Remove the Ridge: Use a sharp blade to carefully remove the raised part of the seed, which is the ridge, especially when you notice that it has gotten hard.
• Slice the Seed: As a last resort, you can make a small cut in the seed’s shell. Careful! Damaging the seed tissue might prevent germination.

Quick Tip: 

• Some old seeds may not sprout no matter what you do.

Shop the Best feminized seeds from us

FAQs

Can You Freeze Cannabis Seeds for Long-Term Storage?

As a general rule, the colder the temperature, the slower the seeds will age. If you follow the recommended storage conditions in this guide, your seeds should stay viable for up to five years and still have a high germination rate.

What’s the Best Temperature for Storing Seeds?

Store your seeds in an environment with a temperature of maximum 5°C. The seeds should be in a sealed, lightproof container in a low-humidity, dark environment.

Final Thoughts

Sure, proper storage is crucial, but what’s even more important is the quality of the seeds themselves. Only buy from reputable seed banks that are well-versed in harvesting and producing seeds with strict quality control measures for optimal freshness. 

Not to toot our own horn, but at Aussie Hemp Seeds, we provide the best feminised seeds that the top growers in Australia trust. Check us out and let us help you start your growing season right!