Robin has a very interesting tip about germinating old seed using bleach, something I have yet to try.
Now that you've seen my seed stash, you can understand why I am always looking for ways to germinate old seed. Over the years I have picked up some tips and have had good success.
1, I soak the seeds in a very weak fertilizer solution that is high in nitrates. They are soaked no longer than 12 hours. the nitrates help to start the process of breaking down the seed coat. I don't soak seed that is smaller than carrot seed.
2. The coffee filters that I place them on are dipped into a solution of week tea with a few drops of hydrogen peroxide. The tea provides some protection from fungus, and the hydrogen peroxide adds some oxygen to aid germination.
3. The filters are then placed into a small plastic bag and then placed in warm location.
4. Once I see the first sign of roots, those seeds are planted and the rest checked twice per day.
5. Some seeds last much longer than others. I am still getting good germination from tomato seed purchased in 1999.
I use 9oz styrofaom cups and add 3 to 4 drops of a liquid fertilizer for the initial soaking. When the filters are soaked I use the same 9oz cup and add a weal tea solution with 5 to 6 drops of hydrogen peroxide.
This method is not fool proof, but I am able to germinate a good amount of seed between 5 and 10 years old.
This year I've had success with 6 year old spinach, 7 year old Swiss chard and pea and 8 year old beet as well as 13 year old tomato seed. My seeds are kept in a cool basement room, no special conditions.
If you have some old seed that you want to still grow give this method or Robin's method a try. I'm going to give Robin's method a try!