using old seeds

Do seeds really have use by date. i hasve not planted now for a couple of years but getting abck in the swing now. i have some seeds unopened in packets that someone bought me for Christmas 3 years ago. should they be ok to use?

Useful table on this very site:

Seed Longevity

Partly depends on the conditions they have been stored in - cool and dry is good, very variable temperatures and damp is not at all good! 

The table shows that parsnip seeds lose their potency quicker than any others - that doesn't mean that none will germinate after a year but most people have enough problems even with fresh seed!

I've also found that the F1 sweetcorn seeds germinate very poorly after a year, whereas if runner bean seeds still look OK, (i.e. not cracking or falling apart) they probably are OK, even after several years.

that's great -thanks

I would abandon them all and start with fresh seed.

  I would have thought that a little drastic without knowing storage conditions and varieties.  I've been sowing lettuce, tomatoes, carrots and most brassicas well past their use by dates from opened packets with good results (both germination and growth)  A couple of years ago I found an unopened packet of lavender seeds that was 12 years past the use by date (somehow it even survived a house move) and was amazed to find every single one of them had germinated.  I now have a thriving lavender bed on my plot.

I think the trick is to sow several seeds more than you would normally and just pinch out the weaker seedlings if vigour is a concern.