Germination Testing — Do It Now to Get Ready for the Season

Now is a great time to evaluate your seeds. It’s a fun rainy (or snowy) day project to pull out the box and flip through the packets. What did well? What did poorly? What can’t you wait to plant again? Perhaps most importantly, what can you take to the seed swap and be sure your gardening friends will be getting good seed?

As you hold an older packet in your hand, one big question comes to mind: Are these seeds still viable? Three years is a good general cutoff date, but some will last much longer. And if you haven’t been as careful as you should have in storage, they might not sprout. So how do you know?

There’s a pretty easy way to find out if the seeds are still good: do a germination test. Here’s one way to do it, in 5 steps. As an example, I will use a test that I began today.

1. Count out a good quantity of seeds. In this test, I used Black Spanish Radish (Raphanus sativus) from 2020. This was the last of a large bag tied up in the garage. I shelled them from their pods until I had 100 seeds.

2. Place the seeds on a moistened paper towel. This will give them a place to germinate.

3. Fold over the paper towel and insert it in a large zippered plastic bag. Lay it flat in a warm place out of the way. I use the top of my refrigerator.

4. Monitor the project daily for the next two weeks. Don’t let the paper towel dry out–the seeds need the moisture to sprout. Just open the bag and sprinkle a little water on the paper, or squirt it with a mister. Keep it moist, but not too wet.

5. Some seeds sprout within a few days, while others can take up to two weeks. When you see the first ones sprout, wait a few more days. Then open it up and count the little green shoots. The seed would be considered viable to share if more than 60 percent of the seeds sprout in your test. A higher number would be much better. At 50 percent or below, it’s best to just toss those seeds on the compost heap and buy (or swap for) fresh seed.

I’ll update this post with the results of my test, so check back in a couple of weeks. Meanwhile, start your own germination test–and post your results to our Facebook page!

Update: 60 Percent Germination

Well, after 10 days I pulled the plastic bag from the top of the fridge and saw some pretty good sprouting. Not great, but good. Turns out my Black Spanish Radish seeds are right on the edge of the viability: just over 60 of the 100 seeds sprouted, a 60% germination rate. I will share the seeds this year while letting people know to sow a little more heavily, and then compost any leftover seeds after this season.

Germinated seeds pushed at the paper towel and peeked out.
Check out the amazing root system on this little radish sprout!

There are other methods and of course advice varies. Here are some germination testing resources:
https://extension.illinois.edu/blogs/ilriverhort/2017-02-03-test-seed-viability

https://www.newstribune.com/news/2021/jan/31/Ask-a-Master-Gardener-Germination-test/

https://www.southernexposure.com/how-to-test-germination/

https://www.highmowingseeds.com/blog/how-to-do-a-quick-germination-test-at-home/

Join us at the Seed Swap!

Interesting lettuce? New tomato? Sunflowers for solidarity with Ukraine? Join the Seed Library for the return of our Great Seattle Seed Swap! It’s our first since 2019, and we can’t wait to share seeds with you.

The swap will be Saturday, April 16, 11 a.m. to 1 p.m. at the Phinney Neighborhood Center, 6532 Phinney Ave. N., in the Community Hall of the Brick Building.

Recent donations from the Organic Seed Alliance of their “Teddybear Sunflowers” and from High Mowing seeds will provide new choices for seed-swappers to try this year.
OSA’s Semi-Teddybear Mix. Photo by Bill Thorness.

See our Facebook event and let us know you’re coming!

Do you have seeds to share? Here’s a guide to our preferences for seed-sharing:

  • Share only seeds of edible plants that your fellow gardeners would grow from seed, such as annual vegetables, herbs and edible flowers.
  • If donating packaged seed, it should be organic or open-pollinated, plant types that will produce seed true to the stated variety. Heirlooms are by definition open-pollinated.
  • If donating home-saved seed, please winnow and clean it off the stems or stalks as much as possible and bring only the seed.
  • If you can’t clean it in advance, plan to spend some time cleaning it the swap. We will have screens and buckets available.
  • All shared seed should be fresh, within three years of purchase or saving.
  • Label all seed donations with seed type, variety if known, and year it was grown/saved.
  • Bring envelopes and a pen to store and label your new seeds.

Look forward to seeing you in person soon!

Winding Down a Quiet Year

Hi friends of the Seed Library! Our quiet gardening season is now at an end. The seeds have been retired to their winter home in a cool, dark back room.

It’s been a tough year to share seeds, with fewer open hours and no chances to get together. We hope that next year will see some return to normalcy. May the autumn bring you peace.

Seed Swap Scenes

An estimated 150 gardeners attended the Great Seattle Seed Swap yesterday, scooping small handfuls of seeds into packets, sitting in on short workshops, and visiting with non-profits and Krista Rome from guest seed company Resilient Seeds. It felt good to rub elbows with other gardeners intent on planning their 2017 vegetable garden, even though it’s too early to plant.

Here are some images from the event.

Paige
Paige, assisted by online searches, helped shoppers identify traits of plant varieties offered.

Checking a list
An attendee checked a list of desired seeds.

P-Patch
P-Patch staff warmly greeted gardeners and shared info on their program.

Seed ball workshop
Christy of the Seattle Farm Co-op added water to a soil-and-seed mixture that was turned into “seed balls” filled with pollinator-attracting flower seeds for a young attendee.

Laura from Seattle Tilth shared tips on basic seed saving in a well-attended workshop.

giant allium seedhead
A giant allium seedhead contributed by an attendee.

Legume table
Beans and peas were popular.

Shopping
Attendees lined the tables to package and share seeds. Many brought packages from their own gardens.

Seed screen
A seed screen at a demo table.

If you couldn’t attend this one, see our Events listing for more area seed swaps.

Clean Seeds at Saturday’s Swap

Want to try your hand at cleaning some seeds? We’ll be doing it this Saturday at the Great Seattle Seed Swap.

We have a bunch of seeds to clean, from easy beans to tiny radish seeds, both in their pods and ready for shelling. But we also have orach, mustard and arugula. You clean it, you can take it home!

Seeds to be cleaned
A variety of seeds are waiting to be cleaned at this Saturday’s swap.

Seed screens
What does a softball have to do with seed cleaning? Come and find out this Saturday at the seed swap!

You don’t have to clean seeds (or bring them) to participate in the Great Seattle Seed Swap.

We have many seeds for sharing, all neatly organized and labeled in glass jars. We have envelopes for you to package a few that look interesting. We have a resource table for you to research seeds of interest. And we’ll have people on hand to suggest how to grow those seeds to become a great part of your garden.