Two years according to the following and assuming it was dried properly...

Here is a link that might be useful: Storing Seeds

That's pretty conservative. Here in the Southwest, corn seeds have been sprouted from graineries abandoned hundreds of years ago. The seeds have been exposed to summer and winter temperatures, but have remained dry (we don't do a lot of moisture here).

I always figure on pretty good germination up to 10 years. With my older seeds, I do pre-sprout them, or start them in peat pots to get the best conditions.

Catherine

I am working on a 3 year old batch of corn seed that germinated at 80% this year.

If you keep it in the deepfreeze it will keep at least 3 yrs. We have allways had trouble keeping sh2 sweet corn seed until we started doing this. The seed companys will not tell you this as they like to sell new seed every yr. BTW forgot to say germ. is stilll 85% after 3 yrs. We keep almost all of our garden seed in deepfreeze from yr. to yr. with ex. results, try it you will like it!

Properly dried and frozen corn seed will give acceptable germination for 5 years. At 10 years, a few kernels will still germinate. I have a strain of Hickory King that I froze in 1994 and that I grew out again last year (2006). Germination was about 3%. I had over a gallon of seed so I just put it in the ground at a rate of 30 seed per foot. The result was an average of 2 plants to 3 feet of row. This was enough for me to save seed again for another 10 years storage.

Fusion

What if stored at room temperature, how long?

I planted a package of sweet corn that was dated '04, I found it in one of my drawers.. I didn't count what I put down, but my germination rate had to be close to 100%. They came up so close to each other, I had to pull most out! If I had known they would have germinated so well, I would have spaced them ever 6 inches or so to that I wouldn't have needed to waste so many.

Thanks Joe. I planted Avalon, from 2005... I triple-planted them just in case and will thin if needed. (See the Supersweet/Triplesweet corn isolation thread.)

Mark