Saving Heirloom Tomato Seeds

comments (6) October 1st, 2009

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Seed Savers Exchange 4th Annual Tomato Tasting event
Seed Savers Collection Curator reminding seed savers to label everything, every step of the way.
Seeds of Velvet Red tomato
Seed Savers Exchange 4th Annual Tomato Tasting eventClick To Enlarge

Seed Savers Exchange 4th Annual Tomato Tasting event


"Why do grocery store tomatoes taste like rubber balls?" a visitor to our 4th Annual Tomato Tasting event asked.

Today, tomatoes travel farther and farther to get to our plates.  And all this traveling means hybrid tomatoes are being bred for traits like storage and disease resistance at the expense of taste, color, and texture.

But then there’s that other question, "Do heirlooms really taste better?"

At the Tomato Tasting, attended by an estimated 1000 people on Labor Day weekend, we tried to get at the heart of this question the best way we know how: "Here, taste an heirloom tomato.  In fact, taste 35."

And as with most questions in life, there were many answers:

"Hard to believe these are all tomatoes."

"I can’t believe how many different flavors there are."

"These tomatoes really are better."

"Gross!"

So maybe not all heirlooms taste better, but with so many to choose from you’re sure to find one that’s right for you and your brood (it just so happens that Velvet Red won "crowd favorite" by a landslide). And once you find that perfect tomato, you only have to buy it once.  That’s because heirloom tomatoes are a great way for home gardeners to get started saving seed.

In nature, ripe tomatoes fall from the plant and slowly rot exposing the seeds, allowing natural weathering to break down the slimy gelatinous coating on the seed.  This is easily replicated through the process of fermentation.  To save tomato seed, seed savers must deliberately remove the coating from the tomato seed.

Here’s how:

1. Take the seeds out of your best looking tomatoes and put them into any container that can hold liquid.  Don’t worry if there is pulp in with the seeds.  Keep as much juice with the seeds as possible.

2. Some seed saving techniques suggest adding water to the mixture.  We recommend not adding water unless the mixture evaporates before it starts fermenting.  This can be done by adding about ½ cup of non-chlorinated water to 1 cup of tomato seed and pulp.

3. Fermentation should happen in 24 hours-4 days.  This depends on many variables such as air temperature or how ripe the fruit is.  A layer of white mold may grow across the top.  Once this mixture has fermented continue to the next steps so seeds do not germinate.

4. Think about where to put the tomato seed mixture because inevitably it will smell. You may want to cover your mixture with a mesh screen to keep out fruit flies.

5. After fermenting, add water and stir.  Mature seeds will sink to the bottom.  If the seed is light enough to float, it is probably not fully formed, mature, or viable.  Don’t save these seeds.

6. Pour off pulpy mixture, but not the viable seeds in the bottom of your container.

7. Pour the remaining liquid into a kitchen strainer and wash thoroughly under the faucet until clean.

8. Drain, and then spread the seeds out thinly on surface to dry.  Any substrate to help them dry as quickly as possible will work: coffee filter, paper plates, paper towel, or wax paper.  It is best to dry seeds out of direct sunlight; this could take up to 4 weeks.

9. Store the seeds in an envelope or seed packet and place in a dry, cool location.  You can assess the quality of your storage conditions by adding the room temperature in Fahrenheit plus relative humidity.  Try to keep that number under 100; the lower the number the better the conditions for seed storage.

But don’t forget to follow the most important rule:  Put a label on everything, every step of the way.  Because in the words of our collection curator, "No one wants to plant something, thinking they have one variety and end up with something else."

So, save seed from your favorite tomato, plant them out next spring and help put an end to rubber ball syndrome, one tomato at a time.

Tomatoes weren’t the only food being tasted at the Tomato Tasting event, check out the recipes from our first ever salsa contest on our Web site: http://www.seedsavers.org/pdf/salsa_recipes_09.pdf

Note from a seed saver: Tomatoes will, most commonly, self-pollinate, so seeds saved will remain ‘true to type’ without worrying about cross-pollination.  However, there are always exceptions.  Some tomatoes can cross pollinate, this is dependent on many factors such as flower shape, environment, and biodiversity.  To ensure seed purity you may want to plant only one variety,spread different varieties throughout your garden, or know which varieties you are planting.


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Comments (6)

jakerios writes: Its good process.
Posted: 4:50 am on February 9th
greencorner writes: Great Idea. Will try and arrange a seed exchange at our local farmers market the last week in September.
Posted: 2:23 pm on September 17th
savannagal writes: Why does one need to ferment the seeds? What does that do for the seeds? Is this just to get the pulp off the seeds? I've never done that and have had no trouble with moldy seeds, or non-germinating seeds. Just wondering. Thanks.
Posted: 11:13 am on September 15th
WhatsTheMuck writes: Have Chocolate Cherry tomato seeds fermenting right now- they are fabulous, a nice winey flavor but good sugar too. I've kept them on the deck with just a piece of tulle wrapped around the container to keep out the bugs, so no smell in the house. If there's going to be rain, I just pop a taller container over top to keep them from getting flooded out.
Posted: 6:52 pm on October 4th
JadaE writes: Great info! I invested in several different tomato seeds from Seed Savers this year...will be fun to save my own next season! :)
Posted: 2:39 pm on October 2nd
ChrisMcLaughlin writes: Fantastic - thank you for this article. I'm finally saving some heirloom tomato seeds this year.
Posted: 5:20 pm on October 1st
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