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Testing Older Seed Germination

Before tossing away old seed or ordering new seeds from your favorite seed catalog you should test the older seeds you have to save you a bit of time and money. Testing older seed germination rates can save you from wasting time, seed starting soil and supplies on seeds that may not sprout. A seed germination test is really simple and can be done by any home gardener with items you already have around the home. Do this seed viability test at home before planting your older seeds.

How to test seed germination rates

How-to Test Older Seed Germination

All you need is older seed or seed that you are unsure of, a plastic sandwich bag, a paper towel or coffee filter. For this seed experiment I decided to test some Royal Burgundy bush beans I had from Botanical Interests that were packaged for 2009.

seed germination in plastic baggie

1. Place 10 old seeds on top of a paper towel.
2. Fold the paper towel and cover the seeds.
3. Place the seeds and paper towel into the plastic sandwich bag.
4. Moistened the paper towel, seal the plastic sandwich bag and place it in a warm location.

The whole thing is then placed in a warm location, at this point make a note somewhere of when you started the germination test. Either write the date on the plastic baggie or in your garden journal. Within a week most seeds inside the dampened paper towel will begin to sprout.

seed germination in paper towel test

Germination Results

10 sprouted seeds = 100% Perfect
9 sprouted seeds = 90%   Excellent
8 sprouted seeds = 80%   Good
6-7 sprouted seeds = 60-70%   Fair
5 sprouted seeds = 50%   Poor

Seeds that fall into the 60-70% germination I would sow heavier than normal. Some gardeners would probably recommend not bothering to plant seeds that germinate at 50% or lower rates.  Instead of discarding these older seeds I would either sow them really heavily or direct sow them in the garden and not get my hopes up too high.

Troubleshooting Old Seed Germination

If none of your seeds are germinating move them to a warmer location like next to a heating vent or on top of the refrigerator. Some seeds may take more than a week to germinate so be patient. Parsley, celery, carrots sprout slower than beans and radishes. Don’t place the baggie in direct sunlight to prevent your seeds from being cooked. If the baggie becomes too wet open it up for a few hours to allow it to dry out some. Don’t cramp your seeds on the paper towel, seeds that don’t germinate may start to mold and infect seeds they’re touching. If the paper towel begins to mold toss it all out and start over.

Get into the habit of conducting seed germination tests on seeds that you’ve had for a while in your seed stash. Even seeds that have been properly stored in a homemade seed bank or are part of a seed library should be tested periodically. If you come across old seeds at a seed swap don’t be afraid of taking those home. This easy-to-do germination test will tell you whether they’re worth planting within a couple of days. Use the seed search engine to find quality information on everything related to gardening with seeds.


  1. I have to try this on onion seeds I bought last year.

  2. Hi MBT,

    I love it, these are like the baggie gardens we used to plant with the kids and tape them to a window. They worked great so I can also see them working for testing seeds.


  3. Really helpful post. Thanks! I have so many seed packets and I'm loathe to throw them out. I've found that nasturtiums and lobelia erinus usually don't germinate the following year.

  4. Good tips MBT! I was just going through my seed stash this morning, and found a bunch of old ones. I don't usually test them, but will try it over the next couple of weeks before I waste valuable garden space and time on duds that might not sprout.

  5. I don't tend to have too many leftover seeds from year to year, but thanks for the reminder of how to test them. And, those sprouted bean seeds are just the cutest!

  6. Great idea! I have LOTS of old seeds to try out, this will save time for sure.

  7. I just put up some seeds today. Last year I went a bit overboard harvesting seeds (think 3,000 morning glories alone:)

    It's the first time in a long time since I went this wild so I figured I'd better see what happens before I get my hopes up.

    Wish me luck and thanks for the tips...

  8. Oh -- that takes me back to the 4th grade when we grew bean sprouts on the heater in the bathroom for a science class! But great to remind us. I tossed out all my ancient seeds about 2 months ago - coulda tried this instead. Oh well, I am I will have old, unlabeled or dated seeds again soon enough - lol!

  9. We used to do this "on purpose" in our second grade classroom - to be able to see both the outside and inside of seeds... Then we'd plant those we didn't dissect and have something to put into the ground later. :-)

  10. I have a baggie full of old assorted sunflower seeds. I might have to test some of them in preperation for international sunflower guerrilla gardening day!

  11. This is a helpful post for me. I have some old beans that i brought from Greece 3 years ago and i would like to grow them in my garden, but i was not sure if they're still alive. Thank you for this tip.

  12. Thanks for the comments everyone. I just realized the reply I posted to you all never went through. Hope you all are checking those old seeds and finding that some of them still have some life in them.

  13. I love this method! It doesn't often fail me.

  14. Thanks for the post. I am going to a seed swap tomorrow, and i will pick anything I like, old or new and do your seed test.

    :) will follow your bog from now on. really helpful tips.


    1. Whats a Baggie! Do you mean a normal plastic bag?



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