How to Save Tomato Seeds (Heirloom & Open-Pollinated Only)
Ferment, rinse, dry, and store tomato seeds from heirloom varieties for next year's garden.
TL;DR
- Time: 1 hour (plus 2–4 days fermentation)
- Cost: $
- Yield:
- Difficulty: Advanced
Supplies
Tools
Steps
Pro Tips
Fermentation smell: It'll stink. That's normal. It's not rotten; it's bacterial fermentation. Open windows.
Don't skip fermentation. The gel coating prevents germination. Fermentation removes it.
Save seeds from multiple fruits. Different tomato plants have some genetic variation; mix their seeds for genetic diversity.
Label everything. After 3 months, you won't remember which jar is which.
Drying is critical. If seeds are even slightly damp at storage time, they'll mold. Dry thoroughly.
Cross-pollination: Tomato flowers mostly self-pollinate, but if you're saving seeds from 2+ tomato varieties, keep them 10 feet apart to avoid cross-pollination.
Warnings
Hybrids (F1) don't breed true. Their seed makes random offspring, often poor quality. Save seeds from heirlooms and open-pollinated varieties only.
Don't eat the fermented seed-gel mixture. It's not dangerous, but it tastes foul and you didn't save seeds to eat them anyway.
Research & Sources
- Saving Tomato Seeds at Home
Dr. Dan Drost, USU Extension Horticulture (2024) - Heirloom Seeds and Plant Variety Conservation
Dr. Heidi Kratsch, USU Extension (2023) - Seed Saving Best Practices
Utah State University Extension (2024) - Sevier County Heirloom Gardening
Sevier County Extension (2023)
Frequently Asked Questions
Why does the fermented seed gel smell so bad?
Bacterial fermentation. It's the same process that makes sauerkraut and kimchi. It's not rotten—it's intentional. The smell means fermentation is working.
Can I save seeds from store-bought heirloom tomatoes?
Yes, if the label says "heirloom" or "open-pollinated." If it says "hybrid" or "F1," no—hybrids don't breed true.
How many seeds can I get from one tomato?
A medium tomato has 50–150 seeds. A large one might have 200+. One seed is enough for a plant; 100 seeds is huge surplus for trading with friends.
Do I need to ferment seeds in water, or can I ferment them in the tomato?
Fermenting in water (scoop gel into a jar) is faster and cleaner. Some folks ferment whole tomato halves, but it's messier.
