A Guide To Long-Term Seed Storage And Preservation

bagseed

Member
Hi all

I think this is a very important topic for anyone planning on keeping seeds for more than a couple of years. Here is a link to an excellent website i found about storing seeds of all kinds: http://www.saveseeds.org/links_storage.html (This is the first time i have been to the site in 12 months and it appears some of the links are a bit outdated and not working but there is still some very interesting info here)

Some edited qoutes from various articles on the site (remember they are talking about seeds from all kinds of plants):

From one article:
Seeds are living organisms that require specific storage conditions in order to remain capable of producing healthy, vigorous plants. High quality seeds are essential to successful vegetable gardening.
While seeds begin losing their viability from harvest, with proper conditioning and storage, some may last years. Many vegetable types will maintain germination rates of at least 50% for ten or more years.
When storing your seeds, be sure to keep them consistently cool and dry. Temperature and moisture are the primary factors that cause seeds to lose their ability to germinate.
Excessive seed moisture increases its respiration rate, can contribute to the growth of micro-organisms, attract insect attack, and reduced viability. Most commercial seeds are dried to less than 10% moisture soon after harvest and held in dry storage during packaging and distribution.
Like moisture, temperature has an influence on the seed's respiration rate. As the temperature increases, so does the respiration rate.
For short-term storage (one year to eighteen months), storing seeds at 35 to 50 degrees Fahrenheit and an air relative humidity of 30 to 40% is desired. The rule of thumb for good seed storage conditions is when degrees F + RH >= 100; the further you can go below 100, the better.
Aside from the conditions mentioned above, here are a few more guidelines:
- Store in the coolest, driest location available to you avoiding temperatures over 70 degrees Fahrenheit. These conditions are easily met by placing a small packet of desiccant (which maintains a dry environment) into a tightly sealed, airtight (not airless), glass container and placed in your refrigerator.
- Make sure that the storage containers are moisture-proof.
- Maintain a fairly constant temperature.
From another article:
In general, longer seed storage life is obtained when seeds are kept dry and at low temperatures. Let (freshly harvested? - note from bagseed) seeds air-dry for several weeks before storing. Do this when the relative humidity is low and the air temperatures are warm. Spreading the seed out in direct sunlight for 6 to 8 hours works well, as long as the seed temperature does not generally exceed 100°F. Drying the seed in shade is usually better. The dry seed should be placed in packages and stored in moisture-proof containers. Containers such as sealed cans or jars with air tight caps work satisfactorily. Storage temperatures between 35°F and 50°F are satisfactory when the moisture content of the seed is low.
An alternate method of keeping seeds dry is to place them in a sealed jar with calcium chloride, silica gel or powdered milk. These substances should not touch the seed. These products absorb moisture from the seeds. Use enough of the product or replace it as needed so that the moisture absorbed from the seed will produce no visible change in the product used.
Which Container To Store Them In And Where To Store Them?

This particular research paper from the same link above: http://www.seedcontainers.net/ contains four links to some excellent info, Please have a look, it's very interesting :) One of the links - "Long term seed preservation: The risk of selecting inadequate containers is very high" details an experiment where 40 commonly used seed storage containers were tested for their ability to keep out moisture, in a humid environment, for 3 years. Only four containers were adecquate to the task.

I think the most important point from the article is that the only container that performed well in the experiment, and can be easily obtained by almost everyone is: glass Kilner (Scotch) jars, with glass lids fastened on a red rubber seal, with a metallic joint and fastening device. You know the sort, everyone's seen those glass jars with the metallic clip top lid and the red rubber seal, #24 in the pic bellow. And most of you probably have an old one in your kitchen cupboard that you've had for years. Just make sure you get a new one because the rubber seal wears out over time. I had no trouble finding some at a local kitchen supplies store.

So after checking out all the info i decided to store my seeds in their original breeder packaging (usually small plastic clip top baggies) inside a couple of new Kilner jars, about 1/3 full of silica gel - the kind that changes colour when it absorbes moisture so that you can easily see when it needs to be removed, and dried out or replaced (i'm just using dried rice at the moment but i have found a couple of companies that sell the silica gel that changes colour, i just have to call them and see if they will mail me some), and the Kilner jars are stored in the bottom of my fridge, inside a small esky (cooler box? dont know what you foreigners call it, but we call it an esky, lol) to protect them from light, and to reduce any temperature fluctuations caused by opening the door, etc. I also have a small jar with a little bit of water in it sitting on top of the esky so that i can see if the fridge gets to cold and starts freezing things - a fairly common occurance in winter, as i'm sure your all aware. Just turn up the temp. dial on your fridge a little bit to fix it.

To begin with i considered storing them in the freezer, but quickly killed that idea when i learned that they have to remain frozen and any thawing and re-freezing (power black-out or repairs, moving house, etc) would ruin the seeds. I also thought about a vacum sealed container, but learned on the above site that seeds need oxygen to remain alive and viable.

I have had bagseed thats been laying around in drawers for 5-6 years or more sprout fine with a 50 to 100% germ rate, but when it comes to expensive beans from top breeders, i think that the best storage conditions you can provide is the only way to go.

If anyone has any info or links to add to the topic, please do :)

Cheers all, happy seed storing
 

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bagseed

Member
Thanks #, i guess i should have done a search before starting a thread, it did cross my mind but then i got excited and started typing.

It is a very important subject and since i missed that other thread i'm sure plenty of others did, but i could have just bumped the old thread of course.
 

PtreeCi

MNS Hall of Fame
-I put seeds in vial and add a piece of cotton to pick moisture if there is some

-then I place vials in zipper bag and into metal box

-then place the box in the fridge, classic around 4°C


-this I use for 10+years with no problems at all..


Never saw decline of germination on strains from reputable breeders, which is something to discuss nowadays tho..
 

svap

Active member
thanks @P3Ci, do you think that a lab fridge is required or recommended?

How long do you think, or know that I can store seeds in the fridge? 15 years from what I understood could be possible with your method and good seeds.

I live in a country where is legal just collecting seeds, and I would like to collect mrNice seeds, especially the limited edition ones.

I want to move in a country where is legal to germinate them in like 15 years, hopefully the law will change here where I live before that, so that I do not need to emigrate for weed :)
 

Big Sur

Well-known member
Bad and outdated information in the OP here. Seeds do not last long at 50 deg. F. Also in a refrigerator, even at 40 deg F, they will not last long in higher humidity. Most magazines and books on weed are completely wrong about long term seed storage and that they cannot be frozen long term. Also the seed container site just has information about plumbers now. Dunno what that is about.

The best way to store seeds for any more than a few months is at 0 F in the freezer. At 0 deg. F humidity is a non factor. Also you can thaw them out and re-freeze them. I have kept seeds in the freezer that are still viable after 45 years. And that through living up and down the US west coast. I get up to 100% germination rates with my frozen seeds. They have been thawed out at least a dozen time now between moves with no problems. Yes, Cannabis seeds do take freezing well. Cannabis survived the ice ages in Asia. Cannabis also grows wild in places that there are hard long frosts and thaws between them in places like Kansas and Kazakhstan. Lab testing of Cannabis seeds has also proved this to be the case.

Read the book, Marijuana Chemistry, the updated version of Marijuana Potency by Starks. He sites several studies done mainly in Japan about freezing Cannabis seeds, and the duration of viability at various temperatures and humidity levels. Basically above freezing humidity is a big factor and they will go off over time. Below freezing, humidity becomes a non factor and they will last indefinately. No brainer there. This is how I managed to save bag weed seed from the 1970s until today, and lots of strains since that time. I do not have to grow them every few years to keep the seeds fresh.
 
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PlantManBee

Well-known member
My reasoning for not freezing is lack of faith in both electricity consistency (blackouts) and the freezer itself. It IS an assumption on my part that freezing and thawing more than once may damage the embryonic plant.

Refrigeration is definitely reliable for at least 10 years IME. At that point, I tend to pop them and either make more or end the line.
 

n2ishun

Well-known member
Refrigeration works, short time.

If you want to preserve for decades and beyond sub zero freezing is required.
I will not go into the method I use, but, I will direct you to Svalbard international seed repository.
https://en.wikipedia.org/wiki/Svalbard_Global_Seed_Vault

There are many examples of viable seeds 10,000 years old recovered and sprouted due to natural storage in the permafrost of russia and random other places.

Name any single seed 100 years old that is viable that has not been frozen.
 

Big Sur

Well-known member
My reasoning for not freezing is lack of faith in both electricity consistency (blackouts) and the freezer itself. It IS an assumption on my part that freezing and thawing more than once may damage the embryonic plant.

Refrigeration is definitely reliable for at least 10 years IME. At that point, I tend to pop them and either make more or end the line.
To repeat, in my collection, I have thawed out my older seeds many times between moves up to a week at a time, so they are not damaged by thawing, or by re-freezing multiple times. Refrigeration is no more reliable and if it is humid in there, simply no good for long term storage at the typical setting of 40 deg F. I am not guessing or relying on faith, or making any assumptions here. These are my results over the past 43 years, based on solid experimental data done in Japan on Cannabis seed storage.

But you can believe and assume whatever you wish... sadly most written material says that you should not or you cannot freeze Cannabis seeds. I do know why this paradigm pervades, but it does. This concept is utterly and emphatically incorrect though. Stored at 0 F deg. or below, your seeds will last virtually FOREVER and at any humidity level. Almost every freezer sold in the US is set to run at zero degrees F.
 
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svap

Active member
Read the book, Marijuana Chemistry, the updated version of Marijuana Potency by Starks. He sites several studies done mainly in Japan about freezing Cannabis seeds, and the duration of viability at various temperatures and humidity levels. Basically above freezing humidity is a big factor and they will go off over time. Below freezing, humidity becomes a non factor and they will last indefinately. No brainer there.
I found the book, thanks for having mentioned it, it is very interesting indeed.

I will not go into the method I use, but, I will direct you to Svalbard international seed repository.
https://en.wikipedia.org/wiki/Svalbard_Global_Seed_Vault
Svlbard uses special three-ply foil packets heat sealed to exclude moisture.

I am wondering, should I open the Mr Nice Seeds and put them in another bag, or should I freeze them as they arrive from MrNice SeedBank?

Thanks to anyone that posted here.
 

PtreeCi

MNS Hall of Fame
I will be placing seeds directly in new vials & vacuum seal in food bags & placing them in an enclosed metal box & place it in fridge.

I think this way, I will not have a problem for some years to come.
 

PtreeCi

MNS Hall of Fame

Growstone

Well-known member
Seeds have their own draw in Freezer. Nothing special, unopened packets/straws into a container, opened packets remaining seeds into kinder surprise containers with strain sticker applied. Can be thawed and refrozen, just like in nature... don't leave in a germinating environment...
 

svap

Active member
thanks Growstone, much appreciated your post.

I love this plant, and I really care about preserving some good genetics for the long term. I do need this plant, but where I live you can legally get it only for terminal illness.

Thanks to all of you that have shared your knowledge here, and of course thanks to the breeders and smugglers. I can not see a crime in cultivating and sharing a medicine. Mr Nice have been an hero, not a criminal.

You are all heroes to me, thank you all.

This sharing knowledge is something I have found only in the free (as in freedom of speech ) software.


Freedom and love to all.
 
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