What's the best way to preserve seeds for planting in a couple of years?

Question:I've got blackberry and catnip seeds that I want to plant at the site of my future home. I won't be able to move for a year or two. How long can seeds be preserved and still grow? How do I preserve them?

Answers:
Blackberries, like tomatoes, need to be "fermented" first. Put them in water until the slimy membrane slips off. THEN dry them. It should take from a couple hours to a couple days