How long do sunflower seeds stay viable?
I'm thinking about getting several kinds, but I might not want to grow every variety every year. These are mostly large-seeded varieties meant for eating.
According to this temperate climate permaculture site, they stay viable for 5 to 7 years. It lists the viability of a number of kinds of seeds, and I recognize the lengths stated for some seeds as being those I've seen listed elsewhere.
However, this site says to consider sunflower seeds viable for the coming season only. It doesn't sound as if they know exactly how long they last, though; so, maybe this is just a precaution.
One of the comments on this site says they stay viable for 'a good few years if kept in the right conditions'. So, I think that backs up the 5 to 7 year claim.