Follow-up April, 2011.
I bought some buckwheat seed in 2008. Got close to 100% germination that year. In 2009 still had good germination. Didn't plant any in 2010. This year (2011), had zero germination.
The effect of buckwheat seed storage duration on major indices of the quality was analysed. Seed collected in 1996 and stored for 30 days (analysed in 1996), seed stored for one year (analysed in 1997), seed stored for two years (analysed in 1998), seed stored for three years (analysed in 1999), seed stored for four years (analysed in 2000), seed stored for five years (analysed in 2001) and seed stored for six years (analysed in 2002) were investigated. The results of investigation have shown that seed stored up to two years had preserved its good production traits. Seed stored longer than two years have shown poor quality traits, and seed stored over three years could not be used - its production traits (germination energy and total germination) confirmed that such seed could not be used for planting. Seed stored over five years, regardless of storage conditions, had no qualitative traits, and therefore no value. It was also observed that longer storage duration induced decrease of seed mass. In regard to fr actions, it was observed that smaller fractions lost their quality more quickly than medium fractions.
Journal-of-Agricultural-Sciences (Serbia and Montenegro). (2003). v. 48(2) p. 135-141.