Should you use out-of-date seeds?

At this time of year, many gardeners will be sifting through packets of seeds from years gone by, wondering if they should risk planting those which are past their ‘sow by’ date.

Grow-your-own expert Huw Richards, author and popular YouTuber, whose gardening channel has over 750k subscribers and who collaborates with hand-tools brand Gardena, admits he’s a risk-taker with many aspects of gardening,

“Seed packets are just guidelines. At the end of the day, a seed either wants to grow or it doesn’t.”

Thoughts on ‘use by’ dates

“I think it’s a bit like what’s happened with supermarkets, so they’ve got rid of a lot of best-before dates for vegetables because it’s purely a thing of a guarantee, yet if that time elapses, they may still be perfectly fine to eat,” says Richards.

Some vegetable seeds will be viable for two years, or up to as much as five years or even more, but as time passes the germination rate will reduce and they may not be as vigorous as plants grown from fresh seeds.

Cucumbers, tomatoes, pumpkins and radishes may last more than five years, while onions, spinach and parsley tend to be less viable in one or two years.

Seeds do degrade over time and the RHS says that you may get disappointing results from old seeds and end up having to start again with fresh ones.

Some vegetable seeds may last longer than others, depending on how they are stored.

Richards says: “If you’ve got a load of seeds left over, just sow four or five in a pot. And if any come through, you think, Oh, actually, there’s life in this seed packet yet.”

Matthew Appleby, editor of Horticulture Week, says he has sown out-of-date seeds with some success.

“They can work. It’s kind of like a sell-by date on a supermarket packet that they are there for safety reasons rather than practical reasons.

“I’ve grown pumpkins and courgettes from ‘used by’ seeds and I have had success but it’s a bit more hit and miss,” he says. “It’s worth having a go but don’t expect so much success.”

Test viability

What about storing seeds?

If you’ve only sown half a packet of seeds because you don’t want too many plants or you haven’t room to sow any more, give yourself a better chance of them being viable by careful storage.

“I would say pop them into an old ice cream tub with a lid. Fold up the seed packet and put them in there or even in a cardboard box, in a cool, dry cupboard in your house,” says Richards.

Make sure there is no moisture build-up in whatever container you put them in, or it may rot the seeds, so you might want to use desiccants like rice or get in your storage containers to absorb moisture. Alternatively, go for an airtight glass jar to keep them fresh.

Seeds purchased in resealable packets are recommended if you’re not going to use the whole packet.

Appleby says you can simply use a peg or tape to reseal an opened packet of seeds, keeping them in a cool, dry, dark place.

So, would you expect less success once the packet has been opened?

“Theoretically, but at the same time, it’s more to do with the skill of the gardener when sowing, using the right temperature, the right potting medium, the right water etc,” he says.