When you check the back of the packet on garden seeds you will notice they have a one-year sell-by date as well as usually something indicating how long you can hold them where they should still have good germination rates. Seeds vary where some are good for around 2 years and others may boast around 8 years. When I was first gardening I thought this was just the way it was. Then there was the first push about the “Doomsday” Vault, otherwise known as the Svalbard vault.
Their goal here is to safeguard seeds though what caught my attention more was proof that with a little work I could also have a seed storage “vault” of my own. I could save any viable store-bought seeds, seeds from my garden, and any gifted seeds. Having a storage thing like that could also help me build a seed stockpile so if someone was ever in need of some seeds I could help them out.
Seed Storage Basics
There are fundamental rules to just storing seeds in general. If you are planning to keep your seeds stored out at room temperature then you need to follow some steps
1) Make sure your seeds are dry
Before storing up seeds they need to be dry. Wet seeds either germinate or rot and there are ideal moisture levels for seeds. So when you process fresh seeds it is important to let them dry out to where they are clearly brittle with no evident moisture. I usually dried mine out on a desk or countertop, some opt to dry them in a dehydrator on extremely low settings.
If your area is very humid a dehumidifier can do wonders, or you can toss in some saved silica gel packets when you move them to a container. You can also get some of the cheap desiccant bags from a supply store, I usually got mine from Amazon.
2) Store in paper
Paper is usually the better way to go when storing seeds and you might opt to leave them in the seed packets they were in from the store or to make your own seed packets. I opted to use small envelopes. The problem with plastic is they don’t allow the air to breathe and often end up with moisture in them which damages the seeds.
I used an old shoebox to hold my seeds and made a bag that would fit around it so I had a “seed purse”. It made it easy to pull out and carry around until I was ready to pot up the seeds. If you choose a plastic container that is definitely when you want to add some silica packets.
3) Keep at steady temperature
Seeds don’t like to be stored in a place where the temperature fluctuates too much. They also need to be kept dry and in the dark. Certain seeds are prone to attracting rodents so that is another consideration. Lost some corn seeds to rodents one year.
How Long Do Seeds Last?
Germination rates will vary seed to seed and between the different types. The max germination rate will be in the first year of the seed. Then every year after there will be some percentage decrease. After about 5 years some random seed out of your box may only have a 10% germination rate vs a 98% or 100% within the first year.
Some people seal their seeds in Mylar bags or glass jars and report a slightly longer life for the seeds where observable germination rate longevity can be helped along. The idea is you throw the seeds into a container, throw in a silica packet and seal everything up.
Storing Seeds Forever in the Freezer
I skipped all the other stuff and went right to freezer storage for my seeds. Using the example of the Doomsday Vault, they stored their seeds in Mylar at these insanely cold temperatures and they expect the seeds to be safe for thousands of years.
So you of course take your very dry seeds, seal them up in a Mylar bag, and chuck them into a freezer. Everything needs to be dry and airtight as freezers can add moisture.
When you desire to use your seeds you want to sit your Mylar bags somewhere to thaw before using them. This helps safeguard from condensation.
I had seed in my freezer that were still okay to use from 2008. I had a dedicated small floor freezer for mine. There wasn’t a lot of opening and closing the door either as it mostly sat untouched.