There’s a lot of reasons to store cannabis seeds rather than just planting them in soil and letting them do their work. Whatever the reason, you need to be sure those cannabis seeds stay viable in the long term. Click here to learn how to properly store your seeds until your ready to plant! If you have some cannabis seeds but are not ready to plant them yet, you need to know how to store them properly. Here's our complete guide. Do you know the best way to store weed seeds in the short term? Is long-term storage possible? Learn all you need to know about how to store cannabis seeds.
How to Store Marijuana Seeds Properly
T here’s a lot of reasons to store marijuana seeds rather than just planting them in soil and letting them do their work. Sometimes you have some seeds leftover from your new favorite weed strain and don’t have the space available where you live to plant it. Other times, you’re buying seeds for later use once you’ve got the time and energy for your weed growing project. Maybe you’d like to hold on to precious genetics until you can seek out another strain to cross it to. Sometimes you’re just stocking up for an uncertain future.
Whatever the reason, you need to be sure those marijuana seeds stay viable in the long term. Properly stored marijuana seeds can last for up to five years and still remain viable, and some strains have been reported sprouting at ten years or more.
However, proper storage is not as easy as it seems, since seeds are looking for any excuse to start sprouting and there are a number of factors that tell the seeds that the time is right to stretch out their roots and branches. Store your marijuana seeds in the wrong conditions and they might end up dead, rotting, or diseased by the time you’re ready to introduce them to the soil.
Fundamentals of Marijuana Seed Storage
First, let’s go over the five main factors to consider when it comes to how to store marijuana seeds, especially for the long term.
Keep Your Marijuana Seeds Cool
When it comes to preserving your marijuana seeds for future planting, temperature is the main consideration. In nature, heat is what tells the seed that the winter’s over, which means that it’s time to break open and start sending roots down and shoots up.
If your marijuana seed is not in the soil, this means that the plant matter inside the seed will begin to germinate. The shell will crack open, letting the plant matter out and moisture, bacteria, and pests in. Without soil to thrive in, the marijuana seed will begin to rot.
41℉ (5 ℃) is the absolute warmest you want your long-term storage spot to be, with the sweet spot being somewhere around 38 ℉.
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It’s very important that this temperature remains stable for the long term. If you are refrigerating your marijuana seeds, your best bet is to place them in a separate unit or a spot near the back. Every time that you open your fridge the temperature fluctuates, which can harm the marijuana seeds over time.
While it’s up for debate whether freezing marijuana seeds is an effective method for long term storage, we don’t recommend it unless you know exactly how to cure and prepare your seeds. Otherwise, the frozen water in the seed’s cells can expand, destroying the cell wall and killing the seed.
Watch out for Humidity
Humidity is another enemy in your battle for storing cannabis seeds long-term because any hint of moisture is another clue to the seed that it’s time to stretch its leafy arms and legs. If the marijuana seed shell breaches before it’s in the soil, rot can set in.
However, you don’t want your marijuana seed too dry either. A humidity level of about 5% is the maximum that you want to allow in order to keep the waxy, protective layer surrounding the seed intact without triggering the seed to split open.
Store Your Marijuana Seeds in an Airtight Container
Besides being dark, you want to expose your marijuana seeds 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 storing cannabis seeds by refrigerating them, make your container as airtight as possible. If you have some vacuum-sealed plastic on hand, even better.
Keep Your Marijuana Seeds in The Dark
Much like heat and humidity, light tells that marijuana seed to wake up because it’s time to spring forth. Even if it’s a halogen bulb inside your refrigerator and not the sun itself, the seed’s natural optimism can still start the flowering process.
Light exposure over time can also damage the surface of the seed, which in turn will damage what’s stored underneath. The solution, much like storing cannabis flower and other products, is to keep your marijuana seeds in a dark or opaque container. Without exposure to light, they’ll keep dozing long term.
Your Marijuana Seed’s Genetics
Some weed strains (and some specific batches of those strains) naturally produce seeds that are hardier and longer-lasting than others. This plays a role in how long you can expect your marijuana seeds to remain viable, so be sure to do some research beforehand.
Storage Methods for Marijuana Seeds
Now that we’ve covered how temperature, humidity, light, air, and genetics work against you when it comes to seed storage, let’s cover the best marijuana seed storage methods.
If you’re storing your marijuana seeds for the short term (a couple of weeks or months), a standard mailing envelope or a tan coin envelope will do in a pinch. If the envelope paper is thick enough, it will protect the seeds from the most harmful ambient light. If the envelope is stored in a cool, dry, dark, and temperature-stable spot like the back of a closet or a drawer, the marijuana seeds should also stay dormant in the short term.
Plus, an envelope makes it easy to write the name of the weed strain, the date of storage, and any other important notes you have. If you want to be extra safe about it, throw some grains of rice or a desiccant pack in there to regulate the humidity.
Of course, this method is only as good at the stability of your home’s climate. If you live in a humid area prone to frequent storms or weather fluctuations like Florida, envelopes will only get you so far without ruining your marijuana seeds.
Unlike a mailing envelope, glass jars are airtight, which makes them much more suitable for storing cannabis seeds long-term. Because many types of plastic can let small amounts of water in overtime, it’s highly recommended that you use glass with rubber stoppers. When storing cannabis seeds long term, you should also throw in a desiccant pack to keep the humidity stable.
Be sure to separate the pack from the marijuana seeds with a couple cotton balls or a paper towel. This will help absorb excess moisture at the start as well. If you have a method to vacuum seal the jar even better. Wrap the jar in something opaque and you’re all set. Marijuana seeds stored at a stable room temperature can last for over a year. Refrigerated they can last a couple years.
If you’re looking to store your cannabis seeds long term, vacuum sealing your seeds in thick Mylar bags can keep your seeds viable for up to half a decade. Because the bags are designed for long-term storage, they’ll work well for your marijuana seeds as long as you make sure they were stored at the right humidity (again, a desiccant pack helps with this) and away from the light. This is one of the best options if you’re refrigerating marijuana seeds.
Seeds of Wisdom
In conclusion, storing cannabis seeds for the long haul is relatively simple. They will stay viable as long as they’re kept away from heat, light, moisture, and air. The more care you put into your storage method, the longer your marijuana seeds will last. However, when it comes to planting marijuana seeds with the most chance of success, sooner is always better.
What are your best methods for storing seeds? Share in the comments below!
How to Properly Store and Preserve Cannabis Seeds [Explained]
If you don’t begin with great seeds, you can forget about producing a harvest of high-quality marijuana. A lot of growers seem to forget one simple fact: Your seeds are alive! Although cannabis seeds are fairly durable, improper storage can ruin them. If you’re paying $10-$20 a seed, losing a full batch is an expensive mistake.
Before your marijuana seeds germinate, they are in a similar state to animals when they hibernate. Like all living organisms, your seeds can die if you don’t take care of them correctly. The good news is that cannabis seeds can last for five years after harvest with proper storage.
In this guide, we outline how to store and preserve your cannabis seeds. We focus on the following:
- Insects & Pests
- Germinating old seeds
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Keeping Light Away from Your Marijuana Seeds
You must keep your seeds in a location that is cool, dark, and dry. It is best if you keep the seeds in their original packaging. When they are exposed to temperature changes or light, cannabis seeds begin using their store of nutrients. This is a disaster because they ultimately won’t have the nutrients to germinate.
When they are exposed to temperature changes or light, cannabis seeds begin using their store of nutrients.
Make sure your seeds remain away from light, as it can directly trigger germination.
What’s the Right Storage Temperature?
The best temperature to store your cannabis seeds at is between 43- and 47-degrees Fahrenheit. The lower the temperature, the less likely your seed is to germinate unexpectedly. Experienced growers tend to have special refrigerators to store their seeds. Ideally, your fridge is a no-frost model. If you can place the seeds in the fruit and vegetable section, that is even better.
Another option is to freeze the cannabis seeds. If you go down this route, please ensure that you vacuum pack them first. Then put them in a dark container. Also, it would help if you germinated these seeds immediately once they come out of the freezer. Don’t allow them to thaw first.
What About Humidity?
Here is a quick overview of what will likely happen to cannabis seeds at different humidity levels:
Your cannabis seeds need a certain level of moisture for germination. If the humidity level gets too high, your seeds will rot in storage. An extremely low level of humidity of around 8-10% is suitable only for long-term storage. If it drops below 8%, you offer any insects present in the seeds the chance to become active and start reproducing.
The Right Storage Options for Your Cannabis Seeds
You now understand that you must store the seeds away from direct light. We have also outlined the need for relatively low humidity and a refrigerator-level temperature. Different options are available depending on how long you intend to store the seeds.
If you only require short-term storage, a dark drawer or cupboard is sufficient. The most important thing, regardless of the duration of storage, is to avoid temperature and humidity fluctuations. Rapid variations in temperature, in particular, can destroy your seeds. If you live in a location with warm daytime temperatures and cold nights, avoid outside storage.
For short-term storage, place the seeds in a container with desiccant. Seal it, and place it in a cool, dark place.
Once you enter medium-term storage (a few months), it is time to use an airtight container. Examples include a mason jar or Ziploc bag. Place this sealed container in the fridge. Remember that opening your fridge can cause significant temperature fluctuations. As a result, it is ideal if you have a second fridge that is seldom used.
Also, you should note that modern fridges have low humidity levels. If the humidity is too low, your seeds will begin using up nutrients.
If you want to store your seeds for at least six months, use a vacuum-sealed container. You can achieve this effect by removing all the air from a Ziploc bag. There are also special vacuum-sealed containers available online. Put the sealed bag in a dark container and put it in the fridge.
You also have the option of placing the seeds in the freezer. Remember, though; you need to germinate them immediately upon removal.
A Note on Insects & Pests
Imagine paying $100+ for seeds, going to the trouble of storing them, only to find that insects ruin them. Unfortunately, all you need is one insect in a container to destroy all of your seeds. The first consideration is to avoid exposure to ultra-low humidity. However, for long-term storage, this is precisely what you are supposed to do!
One option is to spread diatomaceous earth (D.E) where you store them. This is a type of sand that has a fossilized algae base. Crucially, for our purposes, it serves as an excellent natural insecticide. Unfortunately, you shouldn’t use D.E if you plan to store your seeds in a fridge with other food.
Imagine paying $100+ for seeds, going to the trouble of storing them, only to find that insects ruin them.
It would help if you also stored your seeds as high above the ground as possible. This reduces the possibility of a pest like a rodent coming in and feasting on the seeds.
Insects and pests also thrive in dirty storage areas. As a result, you must ensure the storage area remains clean. Otherwise, you won’t just attract pests to your seeds; microbes will form and damage the seeds. Do you want to consume marijuana from contaminated seeds?
You can ‘test’ your seeds once you have removed them from storage. Place them in water. If they sink, they should be fine. However, if they float, it is more likely that they are bad seeds. You can still try to germinate, but there is a greater risk of producing poor-quality cannabis, or else the seeds fail to sprout. You can keep floaters in water for approximately 72 hours to see if they sprout a tail.
If you have old seeds not stored in ideal conditions, there are still a few ways to germinate them.
- Remove the hard ridge with a sharp knife.
- Soak the seeds in carbonated water with germination booster, fulvic acid, or hydrogen peroxide. Use room temperature water, and perform this pre-soak for at least 12 hours in a dark area.
- Scratch the tough outer shell with sandpaper. Believe it or not, this process could help warmth and moisture get inside. This process is called ‘scarring’ and should happen before you soak the seeds.
- Make a small cut into the shell as a last-ditch attempt to get it to sprout.
Final Thoughts on Storing and Preserving Cannabis Seeds
If you purchase marijuana seeds and intend to use them almost immediately, you should have no issues. Even so, it is probably best to keep them away from direct light. In the short-term, a dark cupboard is sufficient as long as the temperature and humidity are reasonable.
Once the goal is to store cannabis seeds for months rather than days or weeks, everything changes. You need an airtight container, which you should store in a fridge. Include a vacuum-sealed container if you plan to store the seeds for several months or longer.
When storing cannabis seeds, you must ensure they are not exposed to germination conditions. This means keeping them away from direct light. Also, store in 20-30% humidity (8-10% for long-term storage) and a cool temperature. Keep the environment clean to avoid pests, and consider the tips above for germinating old seeds.
How To Store Cannabis Seeds
Even though they don’t seem to do much, seeds are alive. They need to be handled with care and kept safe until you’re ready to grow them. If you’re not sure how to store cannabis seeds correctly, don’t worry, we’ve got you covered.
Seeds are pretty pricey, and there’s a lot more to storing weed safely than you might think. If you expose them to the elements and extreme temperatures, they’ll die.
Below we’ll discuss how long marijuana seeds last, the ideal storage methods, the role of environmental factors, and how to germinate cannabis seeds. Let’s get started!
How long do marijuana seeds last?
Seeds require proper protection from the elements to last. If carefully stored, you can extend their shelf-life.
How long do marijuana seeds last? Most last up to six months at room temperature, but this timeline extends for users who keep the seeds refrigerated.
High-quality options can survive up to 10 years, but the duration varies according to environmental factors and the chosen strain. Hardy cultivars can withstand the test of time, while weaker varieties only last for three years.
Even the most expensive cultivars can’t survive in unfavorable conditions. Learn all about the various methods available before you start storing marijuana seeds.
How to store cannabis seeds
Seeds are living organisms. If you don’t take proper care of them, they can die. Using the right techniques for storing cannabis seeds means that you can preserve them for extended periods until you’re ready to plant them.
Before you decide on a suitable method, you need to ensure that the environmental conditions are ideal. Important considerations are:
- Humidity levels
- Temperature fluctuations
When any of the above factors aren’t correct, it can cause your seeds to germinate early or wilt.
If you’re wondering how to store cannabis seeds, light exposure is the first consideration. Seeds are unlikely to germinate when you store them in dark places. Storing your seeds near a window exposed to the sun’s rays can cause roots to sprout.
Too much light can also force the seeds to use their nutrients to survive before germination. This exposure causes the seeds to weaken, and they won’t develop once you plant them.
When it comes to humidity and storing cannabis seeds, you need to balance them carefully. If you have RH levels below 8%, your seeds become vulnerable to pests. Humidity levels above 10% can result in fungi developing and levels above 60% cause wilting and death.
The ideal range is 21–30% for short-term storage. Preserving seeds for longer periods means you need to keep them as dry as possible at 8–10%. Various levels have different consequences for the seeds.
|Below 8%||At these levels, any pests or insects around the seeds become active, reproducing and damaging them.|
|8–10%||The risk of pests still exists, but it’s the optimal relative humidity (RH) for long term storing of cannabis seeds.|
|12–14%||Fungi flourish in these conditions, which harms the seeds and affects their ability to germinate later.|
|18–20%||The seeds may sweat, and heating can cause them to rot.|
|20–30%||These levels are ideal for storing cannabis seeds for short-term use.|
|40–60%||When you increase the RH to 40–60%, seeds start germinating. These are also the optimal levels for cultivating most strains of cannabis.|
|80–100%||These levels are too high for storing marijuana seeds. Within 12 hours, they’ll start drowning, wilting, and dying.|
The best way to store marijuana seeds is in cool conditions, with 43°–47°F temperatures. The cooler it is, the less likely your seed will be to germinate. Many growers use a “no frost” refrigerator. The best place to keep them is in the fruit and vegetable section.
They need to be vacuum sealed beforehand. It’s safe to say that when you store cannabis seeds, the ideal environment is cold and dark with low humidity. Aside from refrigeration, some growers use a freezer or a dark spot at room temperature.
Any fluctuations in these conditions put your seeds at risk. You must keep your containers sealed until you plan to plant them. Opening them exposes the seeds to bacteria and pests.
Choosing containers: the best way to store marijuana seeds
If you want to know how to store cannabis seeds with minimal risks, you must choose the appropriate container. Different options are available depending on the duration of storage. Growers typically select between:
- Ziplock bags
- Mason jars
- Plastic containers
- Mylar bags
- Vacuum sealable containers
How to store cannabis seeds in the long term
If you’re wondering how to store cannabis seeds for more than six months, the most efficient option is a vacuum seal container. Ensure that it’s dark-colored and restricts access to light.
Place it at the back of your fridge or freezer. Once again, you need to ensure the appropriate RH levels. Use a desiccant to maintain the moisture levels and absorb ethylene. Popular options are silica gel packs or uncooked rice.
How to store cannabis seeds in the short term
Storing marijuana seeds in the short term is probably the easiest. You can select a drawer or cupboard that’s cool and dark. Ensure that the spot has a consistent temperature. Containers that work well need to be airtight.
Many growers use foam canisters, plastic containers, and mylar bags. The main factor is that they need to keep oxygen and water molecules out.
The best way to store cannabis seeds in the medium term is in an airtight container like a mason jar, ziplock bag, or vacuum sealable container.
You can use a refrigerator to extend the lifespan of your seeds. Be sure to check the humidity levels, as some refrigerators have low humidity levels.
Method for storing cannabis seeds
If you’re collecting seeds from the buds, you first need to dry them. After harvesting, place the buds in a humidor box for roughly 14 hours, then transfer them to brown bags for 2-3 days.
After that, place them back in the humidor box for another week, whereafter mature seeds should start falling off. This drying and curing procedure helps with the long-term preservation of seed quality. If you’ve purchased your seeds from a credible seed bank, you may skip this process.
The steps for how to store cannabis seeds are:
Step 1: Label your containers for easy identification later. It also minimizes light exposure.
Step 2: Insert a desiccant and place a layer of cotton wool as a boundary to separate it from the seeds. This step ensures that the moisture will be absorbed, and the seeds won’t be disturbed.
Step 3: Put the cannabis seeds on the other side of the cotton barrier and seal the container. Place it in the desired location until you’re ready to plant.
How long can you store cannabis seeds?
You can store cannabis seeds for anything from a few days to a few years. You need to control environmental factors carefully, and the better you are at providing optimal conditions, the longer they’ll last.
The containers you choose, temperature, and humidity levels all play a role in the total duration of safe marijuana seed storage.
How to germinate stored cannabis seeds
After storing cannabis seeds, you first need to establish they’re still healthy and viable. Ideally, they should be dark, round, and smooth. If they’re pale, white, and shriveled, you might not be able to get them to sprout.
A great way of testing them is by popping them into a glass of water. Seeds that sink are more likely to germinate. Ones that float might still grow a root, but the cannabis quality it produces will be poor.
You can try a few techniques for stubborn stored seeds that seem like they aren’t viable.
From the fridge
When you’re ready to cultivate your weed crops, remove the seeds from the fridge. This process is similar to the changes in nature when winter turns to spring. Place them in a glass with room temperature water for 12 hours.
To give them an extra boost, you can add one of the following solutions to the water:
- Fulvic acid
- Germination booster
- Hydrogen peroxide
- Gibberellic acid
Some seeds may germinate during this time. If not, you can still try one of the other germination methods.
If you’ve been storing your marijuana seeds for a long time, the outer shell may be quite hard—scarify the seed may be a good option to break the tough outside layer. Using sandpaper, gently scratch the seeds’ surface to allow moisture and warmth to enter it. You can do this before soaking.
Over time the ridge of each seed gets extremely tough. You can enhance the chances of germination by removing the ridge with a sharp knife or blade.
When you store cannabis seeds for a long time, there’s a chance they might not sprout roots. If all the other methods don’t work, you can use a blade to make a small cut in the shell. Ensure that you don’t damage the inside of the seed.
Short term storage germination
If you’ve only kept your weed seeds in storage for a couple of weeks, you can use the same methods as with newly purchased seeds. Common methods include:
- The paper towel method
- Ziplock bag technique
- Cotton wool germination
The paper towel method
This germination method is popular with marijuana cultivators. It’s affordable, easy, and uses mainly household items. It’s great for when you’re no longer storing cannabis seeds, as you can check for progress daily.
To use this method, you’ll require:
- Two paper towels
- Two dinner plates
- A bowl of water
- Cannabis seeds
The two dinner plates serve as a makeshift germination station.
1: Set out one of the plates as the base of the setup.
2: Wet the paper towels in the bowl of water and squeeze out any excess liquid so that they’re damp, not soaking.
3: Place one paper towel on the plate and space the seeds an inch apart on it.
4: Gently cover the seeds with the second paper towel.
5: Cover it with the plate.
Similar to the environment where you store cannabis seeds, you need to place your setup in a cool, dry place. Check on them daily, and add moisture if they seem to be drying out.
If the seeds don’t germinate within a week, they’re not viable. Check our germination guide for more info on this method.
The Ziplock bag technique
The Ziplock bag technique is quite similar to the previous method. The main difference is that instead of placing the paper towels between dinner plates, you slide them into a ziplock bag.
You store marijuana seeds at a lower humidity level than when you germinate them, and the increase encourages roots to sprout. Placing them in a Ziploc bag traps the moisture and provides the ideal environment for the seeds to flourish.
Germinating using this technique takes between 5-7 days. If there’s no sign of roots developing, discard the seeds.
Cotton wool germination
Growers have used cotton wool as a germination tool for many years. Some use it to start bean plants and other vegetables, but it works just as well for helping weed seeds get started.
This method works best if you’ve been storing the cannabis seeds for a few weeks and it requires:
- Two cotton pads
- A bowl of water
- Cannabis seeds
- A container with a lid
1: Soak the cotton pads in the bowl of water and squeeze out the extra liquid.
2: Smooth the cotton pad flat at the base of the container.
3: Place the seeds an inch apart on the cotton you’ve just inserted.
4: Cover with the second damp cotton pad and close the lid.
Place the setup in a cool, dry place and check on it every 24 hours. If the cotton appears dry, add moisture with a spray bottle. Seeds should germinate within seven days.
Locking up seed storage
Storing marijuana seeds is not as simple as it sounds. If you place them in a cupboard and forget about them for a few months, they’ll likely die.
You need to ensure that the temperature and humidity levels are correct and the space you choose needs to be dark. You also need to consider which container you’ll use carefully. Airtight options provide the best results.
Now that you know how to store cannabis seeds head over to the Homegrown Cannabis Co. store and browse through the wide range of options.
To keep learning about the importance of storing your cannabis seeds correctly, check our Potcast on the subject:
About the author: Parker Curtis
Parker Curtis has around a decade of cannabis-growing experience, specialising in soil-less and hydro grows. He’s mastering outdoor, greenhouse, and indoor grows.