“Can I use last year’s seeds this year?”
“how long will my seeds last?”
Both frequently asked questions in almost all workshops but as with many areas of gardening, they’re queries that can’t be replied to with straightforward answers. Moisture content and storage conditions are the two main factors that govern seed viability and as everybody keeps their seeds in different containers and conditions, this will differ from house to shed.
Seed experts recommend that seeds are stored in sealed containers in cool but not frozen environments (so not in a freezer). My wholesale seed suppliers have advised me that the best storage conditions are in a fridge (I have a shelf totally devoted to the Greenside Up seed collections). It’s also recommended that they’re stored in their original sealed packets (they can be folded once opened) or if not available, seeds should be stored in brown envelopes (which draws moisture away from them).
Advice also given is that seeds generally remain viable for two years from packing, apart from parsnips which should be used within one year. However, it is possible your seeds will last longer (and from my own experience I know most do).
The following is a list that was published in Amateur Gardening that offered for popular vegetable and flower seeds:
Veg and flower seeds and how long they are at their best:
|Veg seed||No of years||Flower seed||No of years|
If you’re unsure whether your seeds are viable it’s quite easy to check by doing a germination test (and now would be a great time to do it before you go ahead and order more seeds).
Just place ten seeds in a row onto a sheet of damp kitchen paper. Carefully roll up and place them inside a clear plastic bag. Label and keep in a warm place. Check after a few days, then after a week to see if any of the seeds have germinated, ensuring the kitchen paper remains moist. Keep checking. If 8 out of 10 seeds have germinated then you’ll know you have an 80% chance of a decent packet of seeds. If only three germinate, order some new ones.
If you have the space, and aren’t overly worried about what will grow, just empty what you have into the soil and see what happens, you never know you could be in with a few surprises!
If you’re mathematically minded, it might surprise you (as it did me) that there’s an equation for predicting seed viability. This equation is from the Kew Royal Botanical Gardens website which explains in detail how to use it and others, and how they were configured.
Lastly if you’re looking for advice on how to choose vegetable seeds, here’s a blog post I wrote in 2010 giving some tips and advice.