How to test if seeds are good: A germination test.

Posted by Anne Fletcher on

Have you ever come across an old packet of seeds and wondered if they'll still grow?  Or you're saving your own seeds, but not sure you're doing it right?  Or perhaps you're not sure which part is the seed?  A germination test is a super easy way to see if seeds are any good.

germination test

This post shows how to do a very simple germination test with paper towels and a plastic bag.

Last week, my daughter and I were sorting calendula seeds from seed heads we'd picked and dried last month, and we had a question.  The seed heads had lots of layers of seed-like parts, but we weren't sure which ones were the actual seeds.  Some looked for sure like seeds -- the smallest, hardest, innermost parts. Others looked kind of like seeds, but also kind of like seed casings. 

calendula seeds for germination testWhich of these layers are the seeds?  The outer shells?  The little curls tucked inside?  All of the above?

We decided to do a germination test to see which ones would sprout.  Here's how to do it.

Step 1: Lay out seeds on a double layer of paper towel.

Germination test for calendula seeds

The mystery, "maybe" seeds are on the left, and the for sure seeds are on the right.  Which ones will sprout?

Step 2: Moisten the towels, fold them closed, and put them in an open plastic bag.

Germination test

Germination test

Get your paper towels moist, but not soggy, like a wrung out sponge, and leave them in an open bag.  The idea is to keep them lightly moist, but allow them to breathe a bit too.  Check on them every day to make sure they're not drying out.

Step 3: Check to see if they sprout!

Germination test

After 4 days, we got our answer:  the "maybe" seeds are, in fact, seeds!  (Do you see that little root poking out the bottom of the curl? So exciting!) We're going to leave them for another week or so to see how many more germinate, but our curiosity has been satisfied.  All layers of the calendula seed head are seeds, even though they look really different.

At the same time, we did another germination test with mizuna seeds I saved in the early summer.  Because they sprout so much faster than calendula, we've got our full test results after just 4 days:

germination test

24 out of 27 seeds sprouted, giving a germination rate of 89%. (24 divided by 27 = 89%. Anyone have a kid working on percentages at school these days? This project is a good real-life application!)  I'm going to leave these for a few more days to see if the last three sprout as well.  But 89% is a good enough rate to feel confident planting this batch of seeds.

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