Sow by dates

[Nordmead]

is this when the seeds genuinely become non-viable or do they just want you to throw the seeds out so you go and buy some more? yesterday i bought some tomato seeds which were somehow packed on the 30th september 2010, and it says sow by 06/11 i would have thought they lasted longer than that

[Alison]

If kept well then your tomato seeds will last for years. I've happily germinated them 5 or more years past their sell by dates and I have my suspicions that it's just a way to get you to buy more. If you're not sure then do a germination test on damp tissue to see if they're OK or if you need to buy more

[bubblewrap]

The RHS recently planted some seeds that were 200 years old & some germinated.

[Nordmead]

thanks for your replies was worried id have to throw them out or give them away after i planted what i wanted

[Jeanied]

I had a packet of parsnip seeds - sow by 2002 - and they are notorious for needing to be fresh each year. Blow me if a few didn't germinate on damp tissue in the airing cupboard!
I think after the sow by date, some of the seeds may die off and never germinate - but they don't all go at once. I think the only people to use that kind of sudden death technology are the GM scientists - certainly not Mother Nature!

[Nordmead]

I think the only people to use that kind of sudden death technology are the GM scientists - certainly not Mother Nature!

so are you saying that F1's are less likely to be viable long after the sow by date

[Jeanied]

No, F1 are not GM, as far as I know. (They just don't produce seeds in the next generation which replicate the parents.)

I was, I think, talking about the 'terminator gene' by which the GM companies make sure the plants produce seeds which are sterile so people can't save them and grow them the next year - one way of making sure people buy new each year!

[Nordmead]

oh i thought they were the same

[MalUK]

Think of them as a guarantee date, rather than expiry date.

[Ruth M C]

Apparently (according to some gardening magazines) the percentage germination rate deteriorates after time. However, I've often kept seeds in their packets beyond the sell by date. On some I've noticed poor germination, with others there has been no change. One type to note that will not last is parsnip. For any chance of getting a good parsnip crop you need to buy new seeds each season. I too am a little cynical about buying new each season but as I germinate the majority of seeds in modules (exception being parsnip and carrots) if germination is poor due to being way beyond the sell by date then I go out and buy some more.
Hope this helps
KR
Ruth