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How Long Are Seeds Good For?

This is a question that comes up frequently, and was recently asked by farmgirl_dk in a discussion on Future House. I thought rather than write a very long comment I would make a post about it here.

When you buy a packet of seeds it almost always comes printed with a message saying the seeds are intended for planting in the current gardening year. The question is, can you keep the seeds longer?

In North America seed companies are generally required by law to germination test seeds before they sell them, and the test results are only valid for a few months (about 6 I think). If seeds do not have a minimum germination rate, the seed companies are not allowed to sell them. Once the period of validity for the germination test expires, they either have to be retested or discarded.

What this means is most of the larger seed companies will simply have a large stock of seeds for a particular plant and germination test them each year. Each year if they pass they sell them, otherwise they discard them.

Outside of North America germination testing is not always required. I’ve certainly on more than one occasion purchased a packet of dead seeds here in Amsterdam.

Few seed companies want to admit they are selling very old seeds, so they are generally not labelled with the year they were actually produced. In order to predict how long seeds will last, you really have to have some idea of how old they are.

Since a very important factor in how long seeds last is how well they are stored, and when you buy a packet of seeds you have no idea if it was handled correctly throughout the whole distribution process, it’s very hard to know the condition of seeds when you get them. This is one of the reasons the validity period of the germination test is only a few months, and they are labelled as intended for use within a short period of time.

What I’ve said so far mostly applies to larger seed companies, and seeds purchased through seed catalogs or at garden centers.

If however you purchase seeds directly from a small reputable seed company, like the ones listed on the front page of this blog, they will generally not only label the seeds with the year they were produced but also properly store them up until the time they send them to you. They also don’t usually sell you seeds more than a year or two old. Assuming you store them properly yourself, it is possible to have a good idea of how long these seeds will last. Of course the same thing applies to seeds you have saved yourself.

How Long Are they Good For?

Every plant is a little different, but assuming proper storage, here are some times for common vegetables:

Tomatoes: 5-10 years

Peppers: 3 years

Sweet Corn: 3 years

Other Corn: 5-10 years

Parsnips: 1 year

Cole Plants: 5 years

Carrots: 3 years

Beets and Chard: 6 years

Lettuce: 3 years

Spinach: 5 years

What Happens When They Go Bad?

When seeds get too old their rate of germination decreases, and the chances of them developing into a plant is less.

In general, the only thing that matters for a healthy plant is the DNA contained within the seed. If you have old seed, you manage to get it to germinate and it grows into a plant, there is no reason why that plant should be any less healthy than one grown from a fresh seed.

Your Own Germination Test

If you have some seeds and you want to know if they are still good, one of the best ways to find out is to do your own germination test. To do this, take a few seeds and set them between a few layers of wet paper towel for several days to a week, then count the number of seeds that germinated and compute them as a percentage of the total number of seeds. A germination rate above 50% usually means the seeds are suitable for planting. Less than 50% means you will probably really struggle to get them to grow, and you should get fresh seeds if possible. A germination rate between 50-80% means you should probably sow the seeds closer together in your garden then thin them after they germinate.

Proper Storage

I’ve made a number of posts in the past on the proper way to store seeds, for example here.

In general, proper storage means in a dry place at a steady temperature, in paper or plastic envelopes or bags. The actual temperature in not too critical, but it’s better if it’s on the cool side. You should always protect your seeds from direct sunlight. The bottom of a closet is a good choice.

For longer term storage there are a number of options, like refrigerating or freezing the seeds. For this to be done properly the seeds must be completely dry and stored in a container such as a glass jar with a rubber seal. These storage options always involve some risk, and shouldn’t be used for short term storage. These storage options are rarely useful for purchased seeds with an unknown production date.

Properly freezing seeds will generally extend their shelf life 10 times over unfrozen seeds, so for example tomato seeds up to 100 years, pepper seeds up to 30 years and so on.

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No to GMOs in Europe

The European Union is in the final throws of approving commercial planting of GM crops, the result of pressure from the US, Canada and Argentina. Enough is enough! Europe does not need GM products.

GM crops do not offer any benefit to the consumer or farmer. There is no evidence that any claims of disease resistance, insect resistance or increased yields made by the manufacturers are true in the long term. The only benefit is for the seed companies, so they can own the rights to the food we eat, and spread that ownership by contaminating the environment and our food with their genetic material.

No to GM in Our Food

0.9% GM material is currently allowed, even in certified organic foods. Just who thought of this limit anyway! This limit should be 0%. There is currently no formal or mandatory testing. Testing should be mandatory, and when food is found above legal limits it should be promptly removed from the market.

No GM for Livestock

Most meat and dairy products in Europe are produced with GM animal feed. There is no reason for this, and it should be stopped at once.

Certified organic animals are not allowed to be fed GM feed, but there is no formal testing for this. Random informal testing suggests 20% of supposed GM-free animal feed in fact contains more than the allowed 0.9% level of GM materials. Mandatory testing and enforcement of these limits should be put in place.

No More Trials

For years now permission has been given for trial plantings of GM crops in Europe.

These trials should stop.  We don’t need any GM crops grown here.

No to Products Made from GM Organisms

Many common products such as rennet used in hard cheeses, vitamins and food supplements, aspartame sweetener and pharmaceuticals are made with the assistance of genetically modified bacteria, yeasts or other microorganisms. There are many suspected or known health problems associated with these products, many very serious and life threatening.

Some of these are certifiable organic ingredients and can be in organic foods!

Those products which can be replaced with alternatives and products which have no true clinical value should be removed from the market, and those remaining should be clearly labelled for what they are.

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Manure and Garlic Rust

As many of you know, garlic rust has been a problem disease in many places in the world over the last couple years.

What’s interesting is some people get rust on their plants, and it’s not serious. This is what happened to me over the last two years. It came later than most other people and it didn’t really seem to cause serious problems.

For other people it’s a very serious problem.

I don’t use manure or any other high nitrogen fertilizer in my garden.

Apparently, most people I know who had serious problems with garlic rust, including someone with a garden 100km (60 miles) from mine, used manure when planting their garlic.

You would think this would be a yes or no question, did you use manure? It turns out it can be a lot more complicated, involve timing, different kinds of manure as well as combinations with other fertilizers.

Also, anyone reading this should realize the use of manure is a bit of a cultural thing. Growing up in the US, we never used manure on our gardens, or at most a small amount. I suspect there are a lot of other Americans who don’t either. I guess most Americans growing up on a farm, or raising rabbits, chickens or other livestock would probably use manure on their gardens, but perhaps not others? Most Europeans, especially northern Europeans seem to use manure each year, often covering their garden with as much as several centimeters.

There you have it. Do you grow garlic? Do you get rust each year, and if so how serious? Do you use manure or similar high nitrogen fertilizer, if so when and how much do you use? Please be specific in your answers. Thank you!

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Real Seed Catalogue Order

Seed Order

I recently placed an order of seeds and tubers with the Real Seed Catalogue in the UK, and I was really impressed.

On the left side of the picture you can see my order receipt. Printed on this receipt (double sided to save paper) are both personalized seed saving and cooking instructions for each item I purchased.

Inserted into each plastic seed bag are very detailed planting instructions, together with common mistakes, problems and general advice. Far more than the usual planting date range, spacing and depth information you usually get.

Literally, every bit of useful information they could have sent me they did.  When is the last time you bought a packet of seeds and got cooking instructions?

Not to be missed was also the following on their receipt:

“This is a not-for-profit company limited by guarantee, so there are no shares, and therefore no shareholders to siphon off funds – instead, all spare income is invested back into our vegetable seed research and breeding work.”

So, while we all refer to them as a seed company, we need to keep in mind they are a little more than that.  I think Europe is very lucky to have a seed company like them.