How to Store Seeds (Plus a Cheat Sheet for 28 Different Veggies)

Although garden seeds are normally marketed with a one year sell-by date, most seeds will last much longer without any special care. And with a little extra trouble, they can last for decades or even centuries!  Keep reading to find out exactly how to store seeds for decades.

These techniques will help your garden seeds to last whether you have leftover store-bought seeds or save your own from your garden!

In this article, I’ll first be going over seed storage basics and how long you can expect your seeds to last. Then I’ll talk about sealing dry seeds in airtight containers to extend their room temperature shelf life. And finally, I’ll go over how to freeze seeds so they really will last decades, if not centuries!

Disclaimer: this page contains affiliate links, meaning if you make a purchase, I may earn a small commission at no additional cost to you.

In a minute, I’ll go into more detail on how to prepare seeds for longer term storage, but first a few basics! 

This is how I store my garden seeds that will be used within the next few years. These basic tips will help your seeds to germinate well during the normal lifetime of that type of seed, anywhere from 2-14 years depending on what it is. 

How to Store Seeds Correctly

#1) Make sure your seeds are dry

To start with, make sure your seeds are dry. If they were recently harvested from your garden they should be left out in the open until completely dry and brittle. If they were accidentally left out in the garden or greenhouse you might need to spread them out to dry again. You can also dry seeds in a dehydrator at no more than 95 degrees Fahrenheit.

If you live in a moist climate, you can throw some silica gel packets in with your seeds to absorb excess moisture.

#2) Store in paper, not plastic

Plastic zip locks are the worst storage option for seeds. The plastic doesn’t allow them to breathe like paper does, but also isn’t airtight so can let moisture in. Plastic has a tendency to collect moisture, harming the life of your seeds.

Seeds should be stored in paper envelopes. You can find free printable seed packets here.

I also like to organize seed packets in cardboard shoe boxes, rather than plastic totes that can hold in moisture. If your favorite seed organizer is plastic, you can still use it by adding silica gel packets. Keep the seeds themselves in paper envelopes.

#3) Keep at an even temperature

Seeds will last the longest kept at an even temperature, in a dry place, and out of sunlight. For me, that is in my home, since all of our outbuildings fluctuate drastically in temperature. It’s also the safest place from rodents!

Seed Longevity Chart

Stored using the basic tips above, this list shows a normal range of seed life that you can expect. 

You’ll probably find that germination gradually drops off over a few years, with a smaller percentage of a seed batch sprouting each year. It’s rare to have a high germination rate one year followed by zero germination the next. 

Sealing Seeds for a Longer Shelf Life

To add a few years to your seeds’ shelf life, or help them out if you live in a wetter climate, you can seal them in mylar bags, or in glass jars to keep them completely dry. 

Before sealing seeds into an airtight container, it’s important to make sure that they are extra dry. You can do this by dehydrating them until brittle or by adding silica gel to the container. (Be sure to not let your dehydrator get above 95 degrees) 

I just opened a packet of onion seeds that had been sealed in mylar since 2014 (7 years ago). Although they had a low germination rate, quite a few seeds still came up. In comparison, I planted some 3 year old onion seeds stored normally in a paper envelope and had zero germination. 

Sealing seeds is a helpful tool to make your seeds last a bit longer. Using this method you can store seeds for decades! Sealed seeds can be stored at room temperature, in the fridge, or in the freezer (more on that in a minute!).

To “seal” seeds in a glass jar, you simply add dry seeds, or questionably dry seeds along with some silica gel, and screw the lid down as tight as possible. They don’t need to be canned (canning temperatures would ruin your seeds).

How to Store Seeds for Decades in the Freezer

Finally, for the longest seed life, you can store seeds in a freezer. This is why the global seed vault is located on a frozen arctic island. Here the mylar sealed seeds from around the world are estimated to last for hundreds, if not thousands of years!

To store seeds in the freezer, it is extremely important that your seeds are very dry. Moist seeds can crack and be ruined in the freezer. 

You can use either the dehydrator technique (no higher than 95 degrees until dry and brittle) or seal them in a container with silica gel for several days or weeks before freezing. I usually use silica gel. I add my paper seed packets, or loose seeds to a glass mason jar with the silica gel. Then it’s sealed, and I wait a week or more to make sure the seeds have time to dry before freezing.

If you want to make sure your seeds are dry enough to go in the freezer, you can hit a seed with a hammer. A dry seed will shatter into hundreds of pieces, while a moist one will just be smashed without breaking apart. Dryness is most important with large seeds, such as beans and corn.

To store seeds, they need to be in an airtight container before freezing since a freezer is moist. Mylar or glass jars are good options (it’s fine to separate different seeds in paper packets or ziplock bags inside a larger jar or mylar bag).

When removing seeds from the freezer, allow the container to thaw before you open it. This prevents condensation from getting your seeds wet when you open the frozen container.

Dry and sealed in the freezer, you can store seeds for decades, if not centuries!

Note on Silica Gel

You can find bulk silica gel on Amazon below. It’s also fine to recycle the silica gel packets that come in vitamin bottles. This is a valuable tool to store seeds long term!