HOW LONG SEEDS LAST

The answer is - it depends. It depends on the seed, on the packaging, and the conditions the packets are stored in.

To start with, we need to be clear that we expect you to sow your seed in the same growing season you buy them in. We have this in mind when we test the seed and date the seed packets, and you should expect good germination in this case. But seeds are living things and you will not get such good results if you forget to plant them for one season and leave sowing them until the following year.

We now supply our seeds in two types of packaging, plastic bags and paper envelopes. The paper envelopes are much better environmentally as they just compost - we hate being responsible for hundreds of thousands of plastic bags dumped in the environment each year.

Different species of vegetables have very different seed life, ranging from the Liscari Sativa which we only sell from harvest til the following spring, because by the summer the seed will be dead, through to melons, where some older gardeners swear by using 5 year or older seed because they believe it gives more fruit.

The table below gives a very rough indication for the most common vegetables of potential seed life, if they start out really good and dry (not just room-dried)

Do be aware that the way in which seeds are stored will affect their life – the following times assume that the seeds have been stored somewhere cool, dry and dark. If seeds get damp or are kept in warm conditions they will keep significantly less well. You'll only reach the top end of the seed life shown below if the seeds are really dry and kept somewhere in an airtight sealed packet (not paper) that stays at a steady cool temperature. If you have an unheated under-the-stairs cupboard, then that's ideal as it will stay fairly constant in temperature throughout the year.

Also, germination is not an on/off state, what will generally happen is that as seeds get older the percentage that germinate will start to drop off, and then at some point will fall to zero.

LIFESPAN OF PROPERLY-DRIED SEED:

Type of vegetable	Rough estimate of seed life
Beans	3 to 5 yrs +
Beetroot, chard & leaf beet	2 to 3 yrs
Brassicas (broccoli, cabbage, kale, brussels, turnips etc)	3 to 7 yrs
Carrots	up to 3 yrs
Courgettes & squashes	2 to 4 yrs
Cucumbers & melons	up to 10 yrs
Lettuces	2 to 5 yrs
Onions/leeks/spring onions	up to 3 yrs max
Parsley	up to 3 yrs
Parsnips	2 yrs max
Peas	3 to 5 yrs +
Peppers & aubergines	up to 5 yrs
Tomatoes	up to 8 yrs

If do you have an old packet of seeds, and wonder whether they are worth sowing, you can always test their germination yourself. 

Put a couple of layers of damp kitchen towel on a saucer, sprinkle a few seeds on it, and wrap it loosely in a plastic bag (so that it stays damp but is not airtight).  Put the saucer somewhere warm - an airing cupboard is ideal – and check after a few days.  If your test seeds have germinated, then you are fine to go ahead and sow the rest, sowing more thickly if only a proportion of them grew.  If nothing is happening, then you need new seeds.