The only thing is when seed finally does start to break down and lose that rating, it may lose it rather quickly. Kerby suggests that if you have any doubts, have your seed tested . If it had dropped, we would replace the seed or do what we have to do. First, it's warm germ and cool germ are re-tested. If either fall below a certain level, the seed is destroyed.
Most seed companies decline to divulge that standard.
It's possible for an entire bag of seed that is a year old to be re-offered for sale, but it's not legal to do without a new label and a new analysis. After old seed is re-tested, it can be blended with new seed. Seed companies typically bend seed, primarily for inventory control. Since Freedom to Farm lifted restrictions on acreage in 1996, the amount of returned seed has increased and inventory control has become much more challenging for seed companies. But seed companies insist that the actual blending percentage is based on maintaining quality control and reducing costs to growers, not reducing inventory.