How to Save Tomato Seeds from Your Garden

A woman's hand holding several ripe cherry tomatoes.

Learn how to save tomato seeds from your own garden in this post. I'll walk you through the simple process of saving tomato seeds and share some expert tips!

How to save seeds from a tomato

I love a flavorful, red, ripe tomato fresh from the garden. In fact, tomatoes are the reason I began gardening in the first place.

It's a sad fact that most tomatoes you'll buy at the market, especially in the winter time, are mealy and tasteless. Garden tomatoes are far superior.

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A rainbox of tomato colors

This year I've discovered un-red tomatoes. 

A few years ago I tried yellow pear tomatoes and loved them, but I'd always thought that black tomatoes were downright ugly and kind of disgusting-looking, and how can you tell if green-when-ripe tomatoes are ripe?

While I still haven't tried a black tomato, this year I grew snow white, black cherry and sun sugar cherry tomatoes and the larger Cherokee purple variety.

Red husky, black cherry and snow white cherry tomatoes

By the way, those "snow white" tomatoes aren't white, they are yellow. Just wanted to clear that up, because I was a bit disappointed in the color. 

They're delicious though, so I won't let that stop me from growing them.

Due to an unfortunate chain of events including a very late freeze, I lost all the tomato plants I'd grown from seed this year as well as the transplants I'd bought and the cuttings I'd kept alive over the winter.

Get your free Tomato Tips cheatsheet so you can grow incredible tomatoes!

It was too late to start more from seed so I had to buy whatever plants I could find at the local stores, and the pickin's were mighty slim, let me tell you.

So I did what any tomato-loving woman would do: I bought more transplants at a flea market while we were on vacation in May, and I discovered some new-to-me varieties that I want to grow again.

You buy plants when you're on vacation too, right? And you fit them into the car to take them home?

Cherry Cola cherry tomatoes growing on a tomato vine.

I haven't seen seeds for sale for some of these varieties though, so I'm saving them from my own garden plants. Which is always a good idea anyway.

Did you know that if you save seeds and replant them every year, after a few years those seeds have adapted to your own garden climate and soil? They are the perfect plants for your garden.

How to avoid tomato cross pollination

Saving seeds from hybrid plants is a game of chance though; you'll need to save them from heirloom varieties to get fruit that's true to the parent plants. 

Hybrids are crosses between two varieties, whether done on purpose or by accident (cross-pollinated by bees or other insects, for example).

Tomatoes are self-pollinated; in other words, they don't require insects for pollination. Instead, the pollen is moved by wind or other movement, so it's pretty easy to isolate a few fruits so that you can save "pure" seeds.

On the other hand, insects CAN cross-pollinate tomato flowers. To avoid cross pollination, you can cover a stem of flowers with drawstring bags made of organza or tulle, with brown paper bags, or even enclose an entire plant in a screened enclosure (although that's rather impractical for large tomato plants).

Cover the flowers before they open, and make sure that the covering is insect-proof.

Now, the secret is to shake the flower stem hard every day so the flowers will be pollinated. You want to avoid cross pollination but you do have to make sure the flowers are pollinated!

When fruit forms you can remove the coverings, but be sure to mark the stem in some way so you'll remember which fruits to save.

Or try this when you plant your garden in spring: separate tomato varieties with a tall crop in between. Planting squash as your barrier crop is another good practice; pollinators will most likely go from a tomato blossom to a squash flower instead of to a different tomato variety.

A large green bowl full of ripe tomatoes for seed-saving. Some of the tomato tops are cracked and split, but that doesn't matter when you're saving seeds.

Save these tomato seeds too!

Cross-pollination actually doesn't happen very often in tomatoes since they are self-pollinating plants. So if you didn't isolate your tomato blossoms a few weeks ago but you still want to save seeds, there's still hope.

You might want to save seeds from the first ripe tomato in your garden, or from the largest, the most-colorful, or the best-tasting. 

Well, you should always save seed from the best-tasting tomato, because next year's best-tasting tomatoes come from the seeds of this year's best-tasting tomato.

How to gather tomato seeds

It's a good idea to save seeds from a couple of tomatoes of the same variety instead of from just one fruit. Genetic diversity is a good thing.

Let the tomato ripen completely, either on the plant or on your counter, then cut it into quarters and scoop out the tomato seeds and pulp with a spoon. 

I've found that the serrated ends of grapefruit spoons are handy for so many things like this, such as removing the pulp and seeds from squash and melons we're going to eat.

Canning jars holding water and tomato seeds. Fementing the seeds in water is the first step in tomato seed saving.

Let the seeds ferment

Put the seeds and pulp into a jar, using a separate jar for each variety of seed you're saving. 

Be sure to identify the seed variety in some way: a taped-on slip of paper, or by standing each jar on a paper towel with the variety name written on it for instance.

Add enough water to completely cover the seeds. 

Cover the jar with something that can breathe, such as a paper towel held on with a rubber band. I cut a piece of paper toweling to fit on top of my canning jars.

Click here for a free Tomato Tips cheatsheet so you can grow incredible tomatoes!

Set the jars in a warm place and let the seeds ferment until there is moldy pulp on top of the water. This might take a week or so.

In this case, mold is good!

When the mold develops, add some more water to the jar so you can pour the moldy scum off the top without pouring out the seeds with it. 

Then pour the seeds and remaining water through a fine wire mesh strainer to catch the seeds.

A woman's hand holding two Sun Sugar cherry tomatoes, tiny but tasty!

How to store your saved tomato seeds

Spread the seeds on a plate or on a paper towel with the variety name written on it, and let the seeds dry for several days. Then scrape them off and into an envelope or baggie.

In practice, I've found that it's nearly impossible to scrape seeds off of a paper towel, so lately I've been using a dinner plate instead. I can chip the dried seeds off the plate with my fingernail.

Then label the seed container with the variety name and date, and store. 

I like to keep my seeds in the door of the refrigerator, even though hubby complains a bit that the entire top shelf is full of seeds instead of ketchup and other stuff.

Pretty easy, isn't it? I know it sounds like a lot of work but it really isn't. It takes time but it isn't time that you have to do something in, it's just "waiting time."

Did you know that it's possible to keep your tomato plants alive over the winter? I like to use both methods - saving seeds and "cloning" my plants.

If you've never saved tomato seeds from your garden tomatoes before, give it a try this year.

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What to do with the green tomatoes in your garden when the first frost is predicted