Moldy Tomatoes? No Problem, Save the Seeds! (2024)

Heirloom tomatoes are so tasty to grow but the seed can be expensive to buy every year. Save money and control the health of your tomato harvest by learning to save your own tomato seed.

If saving seeds is your thing, try doing it with friends! Be sure to read the Seed Swap section of our book, The Do It Yourself Homestead. Don’t have your own copy? Click below to see what it’s about! If you’d like to read a sample from the book, just email me at Tessa@homesteadlady.com. Be sure to let me know it’s the Seed Swap section you’re interested in. With eight chapters of homesteading how-to’s and over 400 pages of homesteading information, there’s bound to be a lot that will interest you!

Garden Nerd

Tomato seeds!! I love tomato seeds. I love opening up a new packet, full of possibilities, and having the little buggers fall out into my palm, all round-ish and sweet. They promise to produce miracles in my garden.

I love tomato seedlings, too. You see them dependably popping up in your seed-starting trays, even though there’s still icy spring weather outside. You can run your hands over them and they smell like summer. And you know, you just know, summer is coming.

Here’s how you can preserve that harvest for next year’s garden by learning how to save tomato seeds.

By the way, if you’re new to seed saving and want to start with your adventures with fewer steps and no fermenting (keep reading), try kale seed. Learn to save kale seed, by clicking here.

How Do I Save Tomato Seed – Hybrids or Heirlooms?

One drawback to growing many tomatoes every year is paying good money for seeds. If you want to grow hybrid tomatoes, you’re pretty much stuck with paying for them every year if you want dependable production.

Hybrid Tomatoes

Hybrids aren’t bad (don’t confuse them with GMOs or anything shady like that); you’re a hybrid, after all. To make you, God took some of your mom and some of your dad and, voila, you appeared in all your awesomeness. However, when you reproduce, your children are created, not your mom or dad.

Hybrid seeds don’t produce true to their parents and so it’s a guessing game as to what you’re going to get in their offspring plant. Even in tomato seeds, which are very happy to reseed themselves, the resulting fruit is unpredictable. One example of undesirable, mutant-child behavior on a hybrid tomato is great vining and plant growth, but no fruit set.

This is why we do NOT save hybrid seed for replanting, as a general rule.

Save Heirlooms Seeds

If you prefer the great taste and seed-saving ability of heirloom tomato varieties, then learning how to save tomato seeds is for you! When you learn how to save tomato seeds, it can help relieve that budget spasm that hits early spring when you place your seed orders. That freak out moment when you ask, “Did I really spend that much on seeds?!”

Don’t get me wrong, I still end up buying new tomato seeds every year because…well, quite frankly, I have an addiction problem. But I’m trying out new varieties in the name of science. Finding fantastic flavors that my family will love. It’s for the children. And I could stop any time. Really.

Steps to Save Tomato Seeds:

I’ve broken this up into three sections but don’t let that intimidate you – this is NOT a difficult process. Saving tomato seed well is more involved than saving something like kale seed, but you can do it.

How to Save Tomato Seeds

Prep Time: 30 minutes

Fermentation Time: 1 hour

Drying Time: 7 days

Total Time: 7 days 1 hour 30 minutes

Difficulty: Beginner to Intermediate

Learn to easily wet process tomato seeds through a fermentation process to better ensure seed planting success in the coming garden.

Materials

Tomatoes
Water

Tools

Knives
Cutting boards
Bucket
Containers with lids, jars or plastic

Instructions

First steps

Carve into the center and opened one a quality tomato so that you can retrieve the seed.
Squish out the seed and put them into any upcycled container with a lid.
It's best to take seeds from several of the same variety of tomato for genetic diversity within that variety. Bear that in mind when you're harvesting tomatoes for seed and take several from each plant.
It's also important to pick your best performing tomatoes for seed saving. So, when you're planting, plant a few of each variety from which you want to save seed just to have a good mix. When it's time to harvest, pick the tomatoes with the characteristics you desire in future tomatoes.

Next Steps

Look around the outside of the cut tomato for any scars, squishes, or cracks and carve them off.
Place the impurities you carved off into the yogurt container with the seeds.*
Squish all the liquid from the tomato on the cutting board into the container.
Add enough water to cover the seeds.
Secure the lid (just so that smell the coming fermentation process didn't escape - it's not pleasant).
Label the container and attach a future seed envelope to the lid so that all the information for that tomato variety is right there, taped to the container. Labeling is SO important!

*These blemishes have the bacteria you want for fermenting tomato seeds. Yes, fermenting! Fermenting tomato seeds is a necessary step in successfully saving them.

Tomatoes have a gel sac around their seeds that is meant to protect the seed until the next season when it's time for them to germinate. In nature, that gel would be broken down and the growth inhibitors would dissipate after the tomato had sat and decomposed through the winter.

Fermenting the tomato seeds in the yogurt container just mimics that process and keeps your seeds healthy.

Final Steps

Put your seeds somewhere warmish and safe on a counter or shelf.
Swirl them gently every day and check them to watch for signs of mold.
Once the seeds have developed a nasty, gloppy mold at the top that covers the width of the container, they're ready for final processing. This takes around a week, but it really depends on how warm it is in your house.
At this point, transfer the contents of the seed container into a small bucket and add some water.
Let it sit for a minute so that the mold layer and tomato bits rise to the top, and then dump off the top, yucky water.
Repeat this process, adding clean water again when you're done. Let them sit to settle again, and then swish the seeds and dump off more gunk. Repeat until your water is clear.
Drain the seeds and lay them to dry on a paper towel or coffee filter. Allow to dry for at least a week and ruffle now and then to move around.

Healthy, viable seeds will sink. The useless ones will float to the top where you can just skim them off and dump them. If you ferment your seeds too long, they'll start to germinate in the container. So, be sure to keep checking the seeds and process them as soon as they're fermented but not sprouted.

A sprouted seed can be immediately planted, if you'd like to try growing a tomato indoors this winter. Or, it can be discarded.

A Quick Note on Kids

Be sure to involved your kids, grand-kids or even neighborhood kids in this process. Learning to save tomato seeds is hands-on, messy, interesting and even gross (what with all the fermenting). That’s a perfect combination for kids! Saving tomato seeds could be a cool science project for school or just a neat way to both teach and hang out with the children close to you.

Passing on this homestead/garden wisdom is a duty – a duty that should be fun! Do yourself a favor and involve some kids in this seed saving adventure.

Do Tomato Seeds Need to Dry Before Planting?

Tomato seeds need to dry before STORING. If you have a greenhouse and want to grow tomatoes year round, feel free to plant wet seed. If you’d like to store them for future use, you will need to dry them.

Drying them doesn’t have to be complicated – lay them out on a screen or mat in a place with good air circulation and no direct sunlight.

Caution

A caution to people with kids or cats or both: put the drying seeds somewhere that curious fingers and f*ckless paws can’t find them.

Tomato Seed Storage – Save for Next Year!

Once they’re dry, pop the seeds into prepared envelopes and put them into your tomato seed file. Be sure to label the packet with:

Variety name
Date
Any special growing circ*mstances from that year like drought or cold

Learning how to save tomato seeds is saves you money and helps you control the quality of your plants.

In fact, you’ll get so good at this seed-saving thing that you’ll need to find a good place to store all those saved seeds. You’ll end up with a lot! We use file boxes with hanging folders for each plant family. I also have folders for the many random delineations I’ve come up with like “bean-ish” and “Zen garden” (my herbs). How do you keep your seeds safe and stored?

This organization will not only serve you well during the growing season, but it will also make it easier to share seeds with your friends. Or, your seed group.

Free Sample

Don’t have a seed group? Remember to email me for that free sample of the Seed Swap section of our book! Tessa@homesteadlady.com. Don’t just settle for my word on the subject, here’s a fellow garden nerd and author to tell you what she thinks of The Do It Yourself Homestead: