How To Save Tomato Seeds So You Can Plant Them Next Year

Transport yourself back to the beginning of summer. You planted a few tomato plants in the hopes you'd have a summer full of tomato sandwiches, tomato pies, and simple lunches of juicy tomato slices with a simple dressing of olive oil, salt, and cracked pepper. A few months later, and one of your tomato plants is going above and beyond. It's delivering a bounty of rich, flavorful tomatoes, and you're wondering how you can recreate this harvest next summer.

The best way to do that is to start your own heirloom tomato operation at home. Yes, that means saving the seeds from your tomato plant and sowing them again next year. It's not something that's commonly done, but it is possible when you have heirloom and open-pollinated tomato varieties growing in your garden.

Here's how you can save tomato seeds and grow them again next year in your own garden.

Why Should You Save Tomato Seeds?

There are two obvious advantages to saving tomato seeds. The first is that you won't have to buy tomato seeds again next year. Tomato seed packets may not be expensive, but why buy them if you don't have to? Second, you have a good shot at recreating a variety of tomato that you already know you enjoy, and you know it does well in your local growing conditions.

Choosing The Right Tomatoes For Seeds

The first step in saving tomato seeds is understanding that not every tomato is going to have seeds that are worth saving. It has to be an heirloom or open-pollinated variety and, on top of those two factors, it also needs to be fully mature and disease-free.

"Figure out what traits you are looking to select for like sweetness, acidity, early ripening, or disease resistance," says Larson Weinstein, Head Farmer at Atlas Farms. "When you find a fruit that meets your criteria, that's the tomato for seed-saving. Do this every season over a lifetime and you’ll be sure to have something special. That’s why they call them 'heirlooms.'"

Harvesting Tomato Seeds

Each tomato can produce up to 100 seeds, so you don't have to go through the harvesting process more than once a season (and you'll still have plenty left over!). Plus, tomato seeds last for up to ten years or longer when properly stored, so you could use the seeds from a single tomato for several years in a row if you don't want to go through the process again.

Here's exactly how to harvest the seeds for a successful tomato season the next year.

1. Choose Your Tomato: Pick a fully ripe tomato from a plant that you know produces juicy, plump tomatoes. There's no point in plucking a tomato from one that has tomatoes that don't fulfill your desired flavor profile.
2. Cut the Tomato and Remove the Seeds: After washing and drying the tomato, cut it in half. Scoop the seeds and pulp into a small, clean jar. The pulp and liquid are necessary to help the seeds ferment over the next few days.
3. Cover the Jar and Ferment: Cover the jar with a breathable material, like a paper towel, and secure it with a rubber band. Keep it at room temperature for up to three days, stirring the mixture once per day. If fungus grows, don't worry. That's all part of the process.
4. Fill the Jar With Water to Separate: After three days of fermentation, uncover the jar and fill it with water. The seeds will sink to the bottom, separating from the pulp. Pour out the pulpy water, then repeat until the water is clear.
5. Dry the Seeds: Strain the seeds to get the initial rush of water out, then spread them on a paper plate to dry. Make sure they're separated into a single layer and stored at room temperature. Shake them daily to make sure they're drying evenly.
6. Store in a Cool, Dark Room: After they've dried completely, usually over the course of several days, place them in a bag or container. Store them in a cool, dark cabinet or room until the next year.

Cleaning And Drying Tomato Seeds

Of all the steps, the last two are the most critical in ensuring a healthy harvest for the next year. "The most important factors when saving tomato seeds are proper drying and storage. It is imperative that the seed is completely dry before it goes into storage," says Hughey. "They need to be dried in a warm, dry and well-ventilated space."

If they are left in a place with excess moisture, it's possible that they'll start to grow mold over the off-season. While this may not damage the seeds, it's best not to take that risk.

Storing Tomato Seeds

"Once dried they need to be stored in a dark, cool and most importantly dry space to insure longevity and proper germination of the seed," says Hughey. Typically, placing them in either an airtight jar or a sealed envelope is the best way to guarantee they'll remain viable.

The seeds should be stored in a cool, dark place, and, often, that means a cabinet that's out of reach and not opened often. They'll be right there waiting for you the next year.