Originally posted 16th November 2015, Updated on 3rd December 2019

So you’ve bought your marijuana seeds.  Are you ready to use them yet?  If not, then you’ll want to know how to store marijuana seeds.  More accurately, you’ll want to know the best way to store marijuana seeds.  After all, you could just store your cannabis seeds in a tub in the fridge.  That, however, would be a really bad idea.

Why is proper storage necessary?

Every cannabis grower starts as a beginner but once you have your own stock of plants, storing your own seeds is a logical next step. Like many aspects of cannabis growth, it can take a bit of practice to get it right, but there are some established guidelines which can help. Basically if you use the right method to store marijuana seeds, there will be a much better chance that they will sprout when you sow them.

Also buying premium marijuana seeds online can be expensive, but it isn't difficult to store them properly so rather than waste your hard earned money, learn how to store them properly and they will remain viable for years to come.

How long can you store marijuana seeds for?

That is an interesting question.  There is no official “use by time” on marijuana seeds.  There are stories of seeds lasting up to five years.  In fact, there’s even the odd story of seeds lasting longer than that.  These stories may well be true.  Marijuana seeds are known to be pretty hardy.  In practice, however, you probably want to use your marijuana seeds within two years.  In fact, ideally, you want to use them as quickly as possible.

If you’re collecting your own seeds, you want to wait as long as possible.  Basically, keep your marijuana seeds on the plant while they’re still getting darker.  Harvest when they are as dark as they are going to be.

What environment is best for storing marijuana seeds?

Outdoors, cannabis plants sleep over the winter and wake up in spring or summer.  You therefore want to convince your marijuana seeds that it’s still winter.

Keep your marijuana seeds in the dark

Winters are when nights are longest.  The longer days arrive in spring.  That’s a signal for germination.  Germination is what you want to avoid (right now).  That means you need to keep your marijuana seeds in the dark.

Keep your marijuana seeds cool

Again, you want to convince your marijuana seeds that it is winter.  That means keeping them cool.  Excess cold shouldn’t really be an issue.  Some people even keep marijuana seeds in the freezer.  Excess heat, however, may start the process of germination.

Starve your marijuana seeds of oxygen

Seeds can survive for extended periods without oxygen.  They do, however, need oxygen to germinate.  You don’t want your marijuana seeds to germinate right now.  Therefore, you need to stop oxygen from getting to them.

Keep your marijuana seeds dry

There are all kinds of reasons why you need your marijuana seeds to stay dry.  First of all, moisture encourages germination.  Basically it triggers the production of ethylene.  Ethylene is a plant hormone.  Secondly it encourages the seeds to start breathing.  Thirdly it encourages the growth of mould and fungi.  Fourthly, it can encourage insect attacks.

Having said that, you don’t want your marijuana seeds to be totally dry.  That can kill them.  You want them to have 2-3% humidity.

Silica Gel

The easiest way to do this is to put some silica gel in with your marijuana seeds.  If you bought the seeds, they may well have come with a package of silica gel.  If not, silica gel is widely available.  In fact, if you buy anything online, you’ll probably get some.  If you must buy it, try anywhere which sells floristry supplies.

Alternatively, for short-term storage, you could use rice.  This only works for short periods because rice becomes soggy.  Then you need to change it while keeping your seeds dark.

Put some cotton wool between your seeds and the silica gel (or rice).  This will help to keep your seeds dry.  It will also reduce the disturbance if you need to change out the drying agent.

What are the best methods for storing marijuana seeds?

Before you can store your marijuana seeds, you need to find a good container.  You want this container to be made out of a single material.  This is because different materials expand and contract at different temperatures.  This makes it very difficult for them to stay completely airtight.

mason jar with yellow lid

Glass is your best bet.  Mason jars are a great choice for keeping the air out.  You would, however, have to add an inner container to block the light.  Film cannisters were the traditional choice.  You can actually still buy these.  You can also still buy film to get the cannisters.  Alternatively, you could buy something like a light-proof container for medicine.

You may be able to find an airtight container made of light-proof glass.  This would be an all-in-one solution.  These containers may, however, be expensive to purchase.

It’s generally best to avoid containers made of plastic or metal.  This can be very hard to keep cool.  Plastic, especially, may cause your seeds to “sweat”, even with a drying agent.

Whatever type of container you use, it’s a really good idea to label it.  If, for some reason, you can only use a small label, just put a number on it.  Then keep a note of what the number means.  This is particularly useful if you’re storing separate batches of marijuana seeds.  It is, however, a good idea even if you only have one batch.  That way if you add future batches, you’ll know which is which.  It also stops you forgetting what you stored and why.

Short term

For short-term storage, your main choices are a cupboard or your fridge.  A cold, dark cupboard is actually ideal.  Basically, it it’s good for root vegetables, it’s probably going to be good for marijuana seeds.

A fridge is a good second choice.  If, however, you’re using a fridge, then you really need to make sure your container is light-proof.  You might also want to put it in a cool-bag for extra protection.  You want to put your container at the back of the fridge.  This is where there is usually the least moisture.  It’s also where the temperature is generally most stable.  The veg shelf/box is often the best place of all.

Longer term

This is where opinion varies.  Some people believe that home freezing is a bad idea.  Other people say that it’s OK as long as you do it sensibly.  If you’re going to try freezing, then you’ll need an airtight plastic container.  Glass containers will shatter.  Regular ziplock bags may not be good enough.  You’ll need proper, airtight freezer bags.  You’ll also need a food-grade drying agent.  Both of these can be bought online.

Once you’ve frozen your marijuana seeds, leave them frozen.  Only defrost them once.  In other words, only defrost them when you’re ready to use them.  Also, defrost your marijuana seeds slowly.  Ideally, leave them in a dark place at room temperature to thaw out gradually.  Keep a drying agent in the container during the process.  You want your marijuana seeds to stay dry until you’re ready to sprout them.

Alternatively, just use a cold, dark cupboard or a fridge.  Marijuana seeds often do just fine there for a good two years.

In short

It’s important to store your marijuana seeds in the right environment.  You want to protect them from heat, light, oxygen and moisture.  Any of these factors can trigger germination.  Marijuana seeds can generally be kept safely for up to two years.  They may still sprout after that.  It’s certainly worth a try.  You will, however, have to cross your fingers for germination.