Preserving Cannabis Genetics: How to Collect and Store Seeds and Pollen
Sometimes a grower has to move on from a certain strain. Maybe you’ve been growing the same strain for a long time and it no longer makes as much money as it used to, or maybe you just want to mix it up and start growing something else and don’t have the space for it.
It can be bittersweet saying goodbye to old genetics, but sometimes it’s unavoidable. You can take clones or keep a mother plant, but those aren’t ideal because they require a lot of care and maintenance, especially if they aren’t producing flower.
Fortunately, preserving genetics for long-term storage is easy and will save time, money, and space in the long run. Through seed and pollen collection, you can hang onto those genetics that you can’t fully get rid of and safely store them for future use.
The Benefits of Long-Term Storage
Cannabis genetics are often sourced from external companies and organizations such as nurseries and seed banks. For the individual grower, saving seeds and pollen removes this reliance on external companies. This is especially true with pollen, as very few (if any) companies offer pollen to the public.
Saving space is a big reason to consider long-term storage of seeds and pollen. Mother plants lay dormant in a vegetative state and take up lots of space. Maintaining this extra space is time-consuming and takes extra resources like water, soil, nutrients, light, and other costly elements, all for something that doesn’t produce flower. Even keeping clones of an old strain around will take up space and resources.
A grower or breeder can also freeze the progress of a breeding project for months or years without losing any of the long, hard work. Endeavors such as phenotype hunting and maintaining desired mothers for breeding and cloning can all be saved for later through genetic preservation. This process is like backing up work on a hard drive.
How to Collect Seeds
Cannabis is for the most part dioecious, meaning that the male and female reproductive organs exist on two separate plants (although hermaphroditic plants do occur). It is also a wind-pollinated plant, so pollen must be transferred from a male stamen to a female pistil via the air in order for pollination to occur and seeds to form.
A female cannabis plant that has received pollen from a male will produce many seeds over the course of its maturation cycle. Upon senescence, when the female plant is fully mature and ready for harvest, its seeds will be ready for stratification and collection.
To collect seeds, it’s important to wait until they are fully mature and ready for harvest. Cannabis with seeds takes longer to mature than cannabis that only produces flower.
To tell if a seed is mature, take a look at its shape and color. Premature seeds will be small and light in color, taking on a beige hue. Fully mature cannabis seeds are more full in shape and size and have a much darker brown hue, sometimes accented by black tiger stripes.
Deseeding cannabis can be done by hand or machine. This process typically takes place after the plant has been dried for one to two weeks after harvest. This way, seeds will have reached their maximum maturity and plant material will be brittle enough to break apart with minimal effort.
When collecting seed by hand, use a fine screen to help catch trichomes that will break off during the process. This material is valuable and it would be a shame to waste.
To release the seeds, simply break up the dried buds over a screen and they will fall out. You can release the seeds en masse by rubbing the flower between your fingers and lightly breaking it apart.
Separate or sift seeds over the screen to remove any unwanted plant matter from the seeds themselves. Brush off the seeds—they should be completely free of any remaining plant material such as leaves, stem, or trichomes, as these elements put seeds at a higher risk for contamination and spoilage during long-term storage.
Male cannabis plants will produce pollen several weeks into their flowering cycle. Once their pollen sacs have opened up and released, the plant will begin to senesce and eventually die. It is important to collect pollen right as the sacs are beginning to open up, as this is the time pollen is most viable.
The best way to harvest pollen for storage is to remove an entire male flower cluster and place it in a sealed storage container for several days. After the cluster has dried, place it over a micron screen with parchment or wax paper underneath, and give it a light shake. This will allow the pollen to separate from any remaining plant matter and fall through the screen and onto the wax paper.
Moisture is a death sentence for pollen viability. Because of this, many breeders opt to mix flour into their pollen at a ratio of 4:1 (flour to pollen) when storing it long-term. This additional step will help keep pollen dry for a longer period of time.
Seed and Pollen Storage
Long-term storage requirements for seeds and pollen are similar. Both require cool, dark, dry, and oxygen-deprived environments for optimal preservation.
When storing seeds, place them in an air-sealed container that doesn’t have any light leaks. Film canisters, medicine bottles (non-translucent), and any sealable storage jar will work fine. The idea is to reduce the amount of oxygen present in the storage space as much as possible. You can also add uncooked rice to the storage container, which acts as an absorbent, to reduce moisture content.
For a cool environment, store seeds in either the refrigerator or freezer. Seeds need a consistent temperature without fluctuation to remain dormant long-term.
As mentioned above, the best way to reduce moisture in pollen is to mix it with flour. For long-term storage, it can be kept in a sealed vial or freezer bag. You can keep it in the refrigerator or freezer, though for optimal long-term storage, the colder the better.
The Shelf Life of Seeds and Pollen
You can expect cannabis seeds that have been sealed and properly stored to last for several years, and in many cases, longer. Seeds may be dormant, but they are still alive. Over enough time, they will lose their viability.
It’s important to continually practice germination testing to be sure your stored seeds haven’t lost all viability. To test this, periodically plant a seed and document its ability to germinate.
Fresh seeds should have a germination rate close to a 100%, whereas older seeds will see a significant drop off over time in their ability to germinate.
Out in the open, pollen may be viable for one or two weeks under normal conditions. However, when frozen and sealed, it can last up to a year and even longer. Pollen is more unstable than seed and even under the most optimal conditions, it isn’t expected to have as long of a shelf life.
For both seeds and pollen that have been frozen long-term, it’s important to avoid defrosting until they are ready to be used. Fluctuations in temperature and moisture content will quickly destroy their viability, so maintain a steady temperature for as long as possible. Warming and freezing multiple times isn’t good.
When it comes time to use frozen seeds, remove them from their container and let them sit out on a dry surface for several hours. Letting the seeds reach room temperature will help ensure a successful germination.
Pollen should also be placed at room temperature before using. Since pollen can be much messier to handle, it’s best to carefully transfer a sample from its long-term storage container to a fresh container before using it to pollinate a plant. This way, you don’t have to use all of the pollen and saved pollen can go back in the freezer with minimal exposure to warm air.
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
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 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!