Frogleg said:

Germination rates *do* decline over time, but I don't believe I've
ever had old seeds produce inferior plants if they *did* germinate.
And the only old seed I've had zero germination with is grass. Lawn
grass, that is. :-) I must say I've never tried onion from seed or
parsnip in any way, shape, or form.

I've noticed, particularly with eggplant seeds and to some extent with
tomatoes, that old seed that do germinate tend to be weaker, in the sense
that even though the do sprout they seem to be less able to pull themselves
free of the seed coat. Sort of like it was all they could do to start the process.

--
Pat in Plymouth MI ('someplace.net' is comcast)

Any technology distinguishable from magic is insufficiently advanced.
(attributed to Don Marti)