Gardening Plants & Flowers Vegetables

How to Save Tomato Seeds to Grow Next Year

By
Marie Iannotti
Garden Writer Marie Iannotti
Marie Iannotti
Marie Iannotti is a life-long gardener and a veteran Master Gardener with nearly three decades of experience. She's also an author of three gardening books, a plant photographer, public speaker, and a former Cornell Cooperative Extension Horticulture Educator. Marie's garden writing has been featured in newspapers and magazines nationwide and she has been interviewed for Martha Stewart Radio, National Public Radio, and numerous articles.
Learn more about The Spruce's Editorial Process
Updated on 09/06/24
Reviewed by
Barbara Gillette
Barbara Gillette
Reviewed by Barbara Gillette
Barbara Gillette is a Master Gardener, herbalist, beekeeper, and journalist. She has 30 years of experience propagating and growing fruits, vegetables, herbs, and ornamentals.
Learn more about The Spruce's Review Board
How to Save Tomato Seeds to Grow Next Year

The Spruce / Hilary Allison

Project Overview
  • Working Time: 1 hr
  • Total Time: 3 days
  • Estimated Cost: $0-$5
  • Yield: Seeds for sowing

Learn how to save tomato seeds from tomatoes you've already grown. Harvesting tomato seeds is easy and allows you to start them indoors the next season when it's still too cold to plant outdoors. the trick is to ferment and dry the seeds correctly. Learn instructions on how to save tomato seeds so they are ready for planting.

How to Save Tomato Seeds

  • Let the tomatoes ripen fully before harvesting seeds from midsummer to fall.
  • Choose the healthiest-looking heirloom (not hybrid) tomatoes to cull seeds.
  • Scoop out the seeds and ferment.
  • Separate and dry the seeds before cleaning and storing them for next year.

When to Save Tomato Seeds

Collect tomato seeds from fully ripe fruits from midsummer to fall. The first step is to choose your best-looking tomatoes. You want to save seed from the finest fruit so that next year's plant will have good genes.

Only save seeds from true-to-seed, open-pollinated (OP) tomatoes, which include all the heirloom varieties. Seeds from hybrid tomatoes may sprout and grow but will often produce tomato plants that revert to one of the genetic parent plants, which can produce much different fruit than what you expected.

Working With Tomato Seeds

Tomato seeds take some work to harvest because they are enclosed in a gel-like sack. The sack contains growth inhibitors to prevent the seeds from sprouting inside the tomato. In nature, tomatoes fall off plants, rot, and ferment to release their seeds. The following instructions replicate and speed up the process to save your seeds.

What You'll Need

Equipment / Tools

  • Mixing bowl
  • Canning jar
  • Colander
  • Airtight storage container
  • Knife
  • Spoon

Materials

  • Ripe tomatoes
  • Cheesecloth or paper towel
  • Paper plate or glass dish
  • Sealable envelope

Instructions

Materials and tools to harvest and save tomato seeds

The Spruce / Meg MacDonald

  1. Harvest the Seeds

    Place the tomato so it's standing up and slice it in half vertically from stem to blossom end. Scoop out all of the flesh with the seeds from both halves into a bowl. In many cases, you can still use the flesh of the tomato for cooking after you scooped out the seeds.

    Tomato seeds harvested by scooping out inner flesh with spoon

    The Spruce / Meg MacDonald

  2. Start Fermentation

    Add a cup of warm water to the tomato pulp. Put the mixture in a sterilized glass canning jar or a mixing bowl to begin the fermentation process. Cover the top of the jar with cheesecloth or a paper towel to keep fruit flies out and reduce the unpleasant odor of fermentation that will develop. Set the bowl or jar in a warm, out-of-the-way spot and allow two to four days for fermentation to occur.

    Tomato pulp mixed with water in glass jar for fermentation next to cut tomatoes

    The Spruce / Meg MacDonald

  3. Check on the Fermentation

    Check the fermentation process daily. Look for a layer of mold on top of the seeds and pulp. Fermentation is finished when bubbles rise from the mixture or when the entire layer of tomato pulp is covered with mold. The seeds will also settle to the bottom of the jar in a watery liquid under a layer of thicker pulp and mold. Stop the fermentation process at this point or the seeds may begin germinating too early.

    Tomato seeds inside glass jar checking fermentation process

    The Spruce / Meg MacDonald

  4. Separate the Seeds

    Remove and dispose of the mold covering by lifting it out of the jar. Alternatively, add water to the jar or bowl and stir or shake vigorously. The good seeds will settle to the bottom of the container.

    Water added to glass jar to separate tomato seeds after fermentation

    The Spruce / Meg MacDonald

  5. Clean the Seeds

    Strain the seed mixture into a colander and rinse the seeds well under running water. Remove any pulp bits and mold so that only clean seeds remain.

    Tomato seeds cleaned with small colander and water

    The Spruce / Meg MacDonald

  6. Dry the Seeds

    Spread the seeds onto either a paper plate or glass dish to dry. Don't use paper or paper towels or the seeds will stick to them and be difficult to remove. Set the seeds in a warm, dry spot and let them dry completely. Shake them on the plate daily so they dry evenly without clumping. Do not try to speed up the process with heat which may destroy the seeds.

    Tomato seeds laid on white glass tray to air dry

    The Spruce / Meg MacDonald

  7. Store the Seeds

    Use an airtight container to store the thoroughly dried seeds. Place the container in a cool, dry place. You can also put seeds in an envelope and place them in a labeled canning jar with the date. Tomato seeds dried and stored correctly are good for up to five years.

    Tip

    It's beneficial to grow heirloom tomato varieties and save their seeds. Many of these flavorful, colorful vintage types of tomatoes are at risk of becoming rare.

    Tomato seeds stored in small white envelope with label

    The Spruce / Meg MacDonald

FAQ
  • What is the most important step when saving tomato seeds?

    When saving tomato seeds, the most important step is making sure they are thoroughly dried before storing. Dry them in a warm spot with good ventilation before cleaning and placing in an airtight container.

  • Is it OK to save tomato seeds without fermenting them?

    Yes, you can save tomato seeds without fermenting them, however this can reduce germination rates so it's recommended to ferment them before storing.

  • Can I plant tomato seeds straight from the tomato?

    While you can plant tomato seeds straight from a tomato, doing so may not result in the best yield or flavor. It's recommended to save your tomato seeds after drying, fermenting, and storing and plant the following year .