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Alright, so you have purchased cannabis seeds (if you haven’t yet then here is our top 10 seed bank suggestions), but don’t want to use them right away.
On the other hand, maybe you purchased cannabis seeds, and they are already fairly old when they get to you. Therefore, you might be wondering how long can you keep cannabis seeds?
Well, it all does depend on how you store them, as well as the quality of the cannabis seeds and the strain, but generally speaking, 5 years is the maximum amount of time cannabis seeds can be kept without them going bad.
The more time goes on, from the very second the seeds are harvested from the parent plants, the chances of successful germination decreases. Let’s talk about how long you can keep cannabis seeds for, and how to best store them to preserve them for as long as possible.
How Long Do Cannabis Seeds Remain Viable?
This is a bit iffy, because there is some variation when it comes to different strains of weed seeds. However, under normal conditions, most cannabis seeds will remain viable for germination for up to 5 years.
Now, this really does depend on the quality of the seeds to begin with. High quality cannabis seeds may stay viable for up to 6 years if stored properly, whereas low quality cannabis seeds, ones coming from a strain that is not so hardy, may only last for about 3 years before they are no longer viable for germination and growth.
The Factors Involved
There are a lot of factors that go into determining how long marijuana seeds stay viable for, mainly light, temperature, oxygen, and humidity, as well as of course the quality of the weed seeds to begin with.
We have heard of weed seeds staying good for up to 7 years, but this is super rare, and even 5 years is pushing it. Under normal storage conditions, it’s not recommended to keep marijuana seeds for more than 3 years at most.
With every passing year, or even every passing month, the viability of the weed seeds will decrease.
What you do need to keep in mind that the fresher the seeds are, the higher the chances of germination will be. If you have high quality seeds, and they have been harvested from the male plants, up to 6 months usually comes with a near 100% germination rate.
After 1 year, you can count on the germination rate decreasing to around 85% – 90%, and this will continue to lower as time goes on. After 3 years, the germination rate will usually be around 50% to 75%, and it just keeps getting worse from there on out.
Let’s move on and talk about how exactly to store your cannabis seeds so they stay viable for as long as humanly possible.
How To Preserve Cannabis Seeds?
Alright, so you are wondering how long weed seeds stay viable for, and how you can store them to ensure that they are well preserved.
So, how do you preserve cannabis seeds for as long as possible so they will still germinate, even after years of storage? Let’s go over some crucial tips on how to store your weed properly to lengthen the period of viability.
First, let’s go over the 4 main factors which can cause cannabis seeds to germinate early, which for the most part are also the same factors which can cause them to take damage, to rot, and to become totally unviable for germination.
One of the most important things to keep in mind is that temperature will cause seed germination, and super high temperatures may cause your seeds to rot from the inside out.
If you are storing your weed seeds, you want to ensure that the temperature is kept fairly low, about 5 degrees Celsius at the very most.
Storing them in a cool place will ensure that they do not germinate, because in nature, more heat signals the start of the growing season, which will cause the seeds to germinate.
Keeping them cool will also ensure that they are not exposed to too much heat which can damage them. Keep them in a cool place, and some people do use the fridge or freezer, something which we will touch on later today.
Did you know that the life of stored weed seeds doubles in time for every 5 degree Celsius reduction in temperature? Yeah, temperature is by far one of the most important factors here.
The next important factor to keep in mind here is light. Once again, in the wild, bright light signals to plants that it’s time to wake up and grow.
So, if you expose your seeds to light, it will spur on the germination process. At the same time, excessive light, even without germination, can cause damage and cause your cannabis seeds to no longer be viable.
Therefore, when storing your cannabis seeds, put them in an opaque container which does not allow any light in, therefore keeping the seeds away from light. Make sure that this opaque container is stored in a cool place.
Ideally, you want your cannabis seeds to be stored somewhere totally dark and not exposed to any light at all.
Another factor which can cause cannabis seeds to germinate prematurely is humidity. You see, weed seeds are fairly dry, and in order to split open, germinate, and start developing the root system, they need a good deal of moisture.
This is why every germination method out there involves exposing your cannabis seeds to a certain degree of moisture. So, if you don’t want your cannabis seeds to germinate too soon, you need to keep them as dry as possible.
On that same note, even if the seeds do not germinate, excessive humidity can cause the seeds to literally rot, which will make them totally unviable for germination. Therefore, you need to keep them somewhere very dry.
A humidity level of no more than 5% at most is recommended for both short term and long term marijuana seed storage. Yes, this can be hard to accomplish depending on where you live, but we will provide some tips for this later on today.
In terms of seed life, it is said that the shelf life of cannabis seeds is generally doubled in time for every 1% reduction in humidity, making moisture another super important factor to keep in mind here.
Yes, cannabis seeds need oxygen in order to germinate, so, without oxygen present, they won’t germinate. Moreover, bacteria and all sorts of parasites all need oxygen too, so if you don’t want your seeds being infested by pests, keeping oxygen to a minimal level will be beneficial too.
This can be hard to accomplish, but any kind of vacuum sealing or airtight container will do fine for this. As you can see, you need to keep your cannabis seeds cool, dry, in a dark spot, and exposed to as little oxygen as possible.
Cannabis Seed Storage Tips & Methods
Use An Airtight Container
If you are going for short term storage, say less than a year, you could use some kind of small airtight container. Lots of people use those little film canisters, or something similar.
Remember that you do want the canister to be airtight to keep oxygen and moisture out, and generally speaking, the smaller the better. You want there to be as little room for oxygen in that canister as possible.
Remember to store this canister in a cool, dry, and dark place. An opaque canister that does not let light in is needed. If you have a glass mason jar, cover it up with something that will make it opaque.
Use A Plastic Bag
What is definitely not recommended is to use a plastic bag, as these don’t do too well when it comes to keeping out light, moisture, and oxygen.
However, if you use a marker to blacken a small Ziploc bag, put the seeds in it, squeeze as much air out as possible, and store it in a cool and dry place, it should keep the cannabis seeds viable for a couple of months.
If you are going for long term storage, say more than a year, the best method is to vacuum seal the seeds using a vacuum sealer. This will remove all possible air, oxygen, and moisture from the equation.
Once you have vacuum sealed the seeds, you can then wrap the plastic in something dark, or even wrap it with some duct tape, to keep light out, but you will still need to store it in a cool place. Generally for this, you can put them in the freezer or fridge.
Fridge or Freezer
Yes, to keep weed seeds cool, many people will put them in the fridge or freezer, which is fine in terms of cool, and even dark for the most part, as there is no light inside of a fridge or freezer.
The only thing you need to be careful of with this is that when you open the fridge or freezer, condensation will occur, especially near the front, so you do want to keep them at the rear. Even better is if you vacuum seal the seeds, then put them in the fridge or freezer.
As this will keep them away from oxygen, moisture, light, and it will keep them cool too. The freezer is better for long term storage than the fridge. If you do freeze your seeds, make sure to defrost them slowly at room temperature.
Now, the freezer is a bit iffy, because depending on the seeds, it may damage them, in which case you might want to stick with a vacuum seal and fridge combination.
How To Tell When Cannabis Seeds Are No Longer Viable?
Well, the easiest way to tell if your cannabis seeds are still viable or not, is by simply trying to germinate them. Now, healthy weed seeds are usually pretty dark, a nice dark shade of green, and they should be fairly round and smooth.
If your weed seeds are really pale in color, even white, or they look all shrivelled, chances are that they will not longer germinate.
However, you really never know until you try. So, choose your favorite method of weed seed germination, and give it a go. If you do it properly, it should take no longer than 3 days for them to sprout.
If you start the germination process, properly, and the seeds do not germinate in 7 days at the most, you know that they are no longer viable or worth your time.
When all is said and done, simply put, the fresher the weed seeds are the better. Fresh weed seeds that are harvested from the parent plant are best used within 2 or 3 months, but yes, storage, both short term and long term is an option.
If you store your weed seeds properly, they may stay viable for germination for up to 5 years, but there is really no guarantee of this. After about 1 year, you are taking a pretty big chance, so the sooner you use those cannabis seeds, the better.