Have seeds you saved last year, but are unsure of their viability? Or maybe you have some old seeds? Here’s how to test your seeds for germination so you know what to plant and how many to plant in order to have a successful garden this year.
I remember back in elementary school taking bean seeds, sticking them in a damp paper towel, throwing them in a jar, and watching them grow. Going through each stage of development, we were able to watch a plant grow from a seed, to a living, thriving plant.
It was awesome.
Life is amazing, folks.
Little did I know, at the ripe age of 9, that we were actually testing those seeds for germination. In fact, I’m pretty sure I was in middle school before I ever learned that term. Even then, it meant nothing to me. I wasn’t always this way….
We’ve saved seeds and have seeds from last year that weren’t planted. Will they germinate? I don’t know. No one knows. But, there is a way to check them out and see if you need to order new seed or if you can use what you just dusted off from the high shelf in the cupboard that you bought four years ago. All in third grade fashion.
Germination Tests to Check Viability of Your Seeds
How to Test Germination
The Paper Towel Germination Test
Just like we all likely did in elementary school, the easiest way to test most seeds is put them in paper towel. Not all seeds can be tested this way, but we will talk about that in a moment. Most seeds can be. I always, always involve the farm girls in this test. It’s so fun and adds to our homeschool adventures.
Grab some of your paper towels. Get a marker and mark the type and the date on the top of the towel. Now, go ahead and dampen your paper towel. I use a spray bottle for this. You want your towel to be wet, but you don’t want it to be dripping. So keep that in mind. If it’s too wet, your seeds are likely to mold. This is especially true for seeds in the cucurbit family.
Grab 5-10 seeds that you don’t mind sparing. If you don’t have 5-10 seeds to spare, it’s going to be the luck of the draw come gardening season, folks. So, you may want to order more of those….
You can begin by lining the seeds about an inch from the top of the paper towel about 1″ apart.
Fold the towel in half over the seeds.
Now, you can stick them in a mason jar, or a plastic bag or even a Tupperware tub. Anything that has a lid will work. You just want it air tight this will help maintain moisture and temperature. Place a lid on it and set them somewhere out of the way. For seeds like peppers that like it warm to sprout, you could try placing them in a window or put the jar on a heat mat. For most seeds, especially cool crops, just a cool place on the counter will do.
After a day or two, you’ll want to check on your seeds. This is especially true if you’re unsure of how long it will take to germinate. See if any of your seeds have sprouted, if they have, you can remove them from the test, put them in the compost, and record the number in your garden planner. If any seeds remain, add water to the towel and put them back in the jar.
You can check them again in a few days. And keep the towel moist, but not dripping until you’ve concluded the test.
Once you have concluded nothing else is going to sprout, you can toss everything in the compost and be finished. Large seeds will sprout the quickest, usually only taking a couple of days. Most seeds will germinate within a week. A few will take a few weeks to germinate. So, be patient, and if you aren’t sure how long it should take to see some viability, check your seed packet.
The Jar Germination Test
Some seeds actually require light to sprout. This is especially true of most herbs. Again, this information is usually located on the seed packet. If it says to surface plant seeds, they need light. For these type of seeds instead of wrapping the paper towel around them, you’ll put a few paper towels together, get them wet, and place the seeds on top.
Then, you’ll just place them in a mason jar, ziplock bag, or other clear container and put them near a light source. The rest of the directions are the same. Gently spray the seeds when moisture levels decline on the towel to keep it moist. That is it.
A Note on Testing Peppers and Tomatoes
Peppers, tomatoes, and a handful of other flower seeds require potassium nitrate to germinate. Since paper towels and water don’t contain this substance, you’ll have to improvise. Instead of squirting the seeds with water, you’ll want to make a water/potassium nitrate solution if you want to test these types of seeds.
You can find potassium nitrate at the garden center. You’ll want to add a half teaspoon to every quart of water. You can save this in a labeled spray bottle to use to spray the seeds when necessary.
What to Do With The Results
Once you’ve finished your tests, make sure you write everything down in your log. You can calculate the germination percentage by dividing the number of healthy seedlings by the total number of seedlings, then multiply by 100.
If you have a really low germination rate, first you can try sprouting them in seed starter and seeing if that helps (some seeds just need some soil to get them going). If you do that, they may be salvageable to put into the garden, unlike the small sprouts from the paper towels. So, not all is lost.
Another option, especially if you know for sure the seeds should have germinated using the methods mentioned above, it’s probably time to purchase new seeds. While you can plant the seeds that showed low germination rates, I wouldn’t expect too much. And if it’s something you really want to grow, you need to make sure you have fresh, viable seed.
Now that we’ve all had fun conducting science experiments with our littles (or by ourselves) we know what we can and can’t depend on as far as seeds we’ve got lying around.
If I had an endless supply of seeds, I’d check more of them, just because it’s winter and I like watching things grow. Alas, I don’t….
Spring will be here soon, Danielle. Soon.
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