Save tomato seeds for next year’s garden, it’s easy and fun. And, it will save money for other garden necessities.
Most seeds of annual flowers and vegetables can be collected, saved and dried for next year’s garden. But tomato seeds require one additional step, which is fermentation.
Tomato seeds are enclosed in gel casings. Mother Nature has designed the casings to include growth inhibitors, which prevent the seeds from sprouting inside the tomato.
In the garden, these casings break down naturally. When tomatoes fall to the ground the fruit decays. The fermentation step allows this process to accelerate, ensuring a better germination rate next spring.
1. Choose your favorite tomato varieties
Save seeds from heirloom tomatoes and open pollinated tomatoes. These varieties remain true to their type from their own seed. Next season’s plants will maintain the same characteristics as they previous ones.
Hybrid tomatoes are bred from two parents of different varieties. It’s unpredictable whether or not they will produce seeds that keep their characteristics from season to season. They may not resemble the hybrid parent.
2. Extract the tomato seeds
Wash the tomatoes to remove dirt and contaminates. Dry and slice the tomatoes in half at their equator. Scoop out the seeds with a spoon.
Place the seeds in a jar; canning jars works well for this.
Add water to the tomato seeds and pulp, stir the mixture and loosen the tomato pulp from the seeds.
Cover the container with plastic wrap. Poke holes in the wrap so air can move; cheesecloth will work as well. If using a jar, punch holes in the lid or leave it loose. Air circulation will help the fermentation process. Fermentation causes air to expand. Tightly fitted lids could cause the container to break during fermentation.
Label each container with the name of the tomato variety.
Place the container in a warm, protected area, out of direct sunlight. 70º-80º F is the ideal temperature for fermenting seeds. Avoid any drafty areas.
3. Fermenting tomato seeds
Watch closely to note when fermentation begins.
Open the jar each day and stir the seeds. Replace the cover and return the container back in its warm area. Repeat for 2-7 days (the average time needed is 4-5 days). The mixture will turn dark and emit odor as it ferments.
Look for these 3 signs of fermentation:
• Seeds separate and sink to the bottom
• White, foamy mold may form on the top, which is harmless to the seeds
• Bubbles begin to rise to the top of the container
Fermentation dissolves the gel casings around the seeds. Remove seeds from the liquid as soon as fermentation begins. Seeds left in the liquid may begin to sprout; avoid this when saving seeds.
4. Rinse the seeds
Properly rinse tomato seeds to stop the fermentation process, separate the pulp from the seeds. Separate the good seeds from the bad.
Remove the foamy mold from the top of container. Rinse the seeds by adding water to fill the container, stir the mixture several times and then wait 10 seconds. Good seeds will sink to the bottom of the container; bad seeds will float to the top. Pour off the liquid and discard bad seeds.
Repeat as needed until all pulp, mold and debris is rinsed from the seeds. Continue until the remaining seeds have settled to the bottom of the jar, the water is clear and no seeds float to the top of the jar.
When seeds are thoroughly rinsed, pour them into a thin-gauged wire mesh kitchen sieve to remove the remaining water.
5. Dry the seeds
Examine the seeds carefully to make certain they dry before storing.
• Stir and dry: spread tomato seeds in a single layer on a paper plate, mesh screen on a plate, parchment paper, waxed paper, or a coffee filter to prevent sticking. Remember to label each tomato variety
• Dry seeds in a warm area to dry, away from direct sunlight
• Shake or stir seeds daily to prevent clumping and allow even drying.
• Seeds will dry in 1-3 weeks
• Don’t attempt to heat seeds as they dry
6. Storing tomato seeds
Make sure seeds are 100% dry before storage. Otherwise, moisture will allow mildew and rot to spread.
• Allow seeds to dry for 1-3 weeks, dried seeds will be very hard
• Store dry seeds in paper envelopes or plastic bags
• Add silica gel packets to seed bags as moisture deterrent
• Label seeds with variety and date