To the inexperienced gardener, you may believe that the seeds you buy from the store or collect yourself are good only for one growing season. They even put an expiration date on most seed packets that is often for that same year. But, the secret truth is that seeds have the ability to last an tremendous amount of time given certain factors. The most successful of these techniques are Drying and Freezing, and guess what, they are easy!
DRYING
It may seem like it is sucking the life out of them, but in truth drying is the best way to bring your seeds to true dormancy. Along the edge of the Dead Sea in Israel, 2000 year old seeds were found in the ruins of the Masada fortress and in 2006 they were planted and produced a healthy Date Palm! By reducing the moisture in your seeds, you remove the factor that promotes decay and eventually destroys your seeds. It is hard to remove All moisture, but we can quite easily bring the moisture content down to approximately 8% which is perfect for extending seed life.
How
Air-drying is not enough and will not preserve your seeds properly. It will not pull enough moisture out of them to prevent them breaking down. While some may promote using a food dehydrator, oven or sun-drying, I find these all far too difficult to control. Getting seeds too hot can actually make them sterile. Instead, the best way to dry your seeds is to use Super-Dried Rice. This way, instead of drying the seeds themselves, you are drying the rice and then using it to suck any existing moisture out of your seeds.
You Will Need
2-3 times more Rice than Seed (too little rice will not work)
A large Canning Jar with lid
Mesh Bag or an Old Pair of Stockings
1. Spread enough rice to fill a canning jar half-full onto a baking tray. Do not grease your pan.
2. BAKE the Rice on the tray for 45 minutes or until it is Bone Dry
3. Place the Still-Warm Rice into your Canning Jar and tighten lid ( This important as it prevents moisture from the air from re-hydrating the rice)
4. WAIT patiently for it to cool
5. Once it is completely cool, place your seeds in a mesh bag and place the bag in the jar with the rice, then re-tighten the lid.
6. After 14 Days your seeds will have been thoroughly dried and are now dormant and ready to store! You can either keep them in the same jar you have been drying them in (after removing the rice), or you can move them to a heavy duty Ziploc bag or a Foodsaver vacuum sealed bag. *(Studies have been conducted that show devoiding properly dried, dormant seeds of air does not effect viability, they are just).
7. STORE your seeds in a cool place (a cold storage, fridge or freezer are ideal) and they will last up to 10 Years or Longer!
FREEZING
While drying your seeds until they are dormant may buy you a few extra years of use, freezing that same dormant seed may extend its life almost indefinitely! If you thought a 2000 year old seed sprouting was impressive, then the knowledge that a 30,000 year old Frozen seed found beneath 125 feet of permafrost in Northeastern Siberia has also sprouted, should blow you away!
How
1. Follow the instructions above for removing moisture from your seeds and turning them dormant.
2. Seal them in a moisture/air proof bag. (For freezing, I prefer the Foodsaver bags.)
3. Place them in your freezer…pretty simple!
http://www.http://www.newscientist.com/article/dn14125-jesusera-seed-is-the-oldest-to-germinate.html
Larinda's Garden 
What is the purpose in using this method? It seems putting the warm rice in the jar and then putting in the seeds would trap moisture from the still-warm rice. Interesting method though. I have not heard about this one. Thank you.
You are actually placing the warm rice in the jar ALONE. This allows the rice to cool while not re-absorbing moisture from the air. It is only once it has COOLED COMPLETELY that you place your seeds in it. If for any reason you find the rice is still moist (i.e. beads of moisture on the jar), before you place your seeds in it, place your rice back in the oven on a tray, and heat it for a longer period of time. I could possibly see this scenario in an incredibly humid environment. The whole reason for this step is to get it bone dry, with absolutely no moisture left. At that point the dry, cool rice will pull all the remaining moisture out of the seeds you are saving, thus making them dormant. Thanks for making sure this is clarified. It is a fantastic seed-saving technique and I hope you try it!!!
Thank you so much for sharing this great information on your website! I love this process and I have used it to store many seeds and subsequently save a lot of money in the process. The truth is that if there ever was a long-term emergency we would need the knowledge of how to save and store our own seeds, and like you said, it really is easy!