Seed Saving — Tomato (Fermentation Method)
Save seeds from open-pollinated tomato varieties using the fermentation method. This removes the germination-inhibiting gel coat and kills many seed-borne diseases. Tomatoes are ideal for beginning seed savers as they are largely self-pollinating.
Version History
Version 1.0 Current
Effective: 2026-03-24Initial version
Procedure Details
The fermentation process produces a mild odour. Work outdoors or in a well-ventilated area. Wash hands after handling fermenting material.
Requirements:
- Ripe, healthy tomatoes from open-pollinated (not F1 hybrid) varieties
- Glass jar or cup
- Fine mesh strainer or sieve
- Paper towel or plate for drying
- Seed envelopes and labels
- Water
Important: Only save seed from open-pollinated or heirloom varieties. F1 hybrids will not grow true to type.
Procedure Steps (Version 1.0)
Select 2-3 of the best, most typical fruits from your healthiest plant. Choose fully ripe tomatoes that represent the variety well (size, shape, colour).
Cut the tomato in half across the equator (not stem to blossom). Squeeze the seeds and gel into a glass jar or cup.
Add a splash of water to the jar (about equal volume to the seeds and gel). Stir gently.
Cover the jar loosely (not airtight — fermentation produces gas) and place in a warm spot out of direct sunlight.
Let ferment for 2-3 days. Stir once daily. A layer of mould on top is normal and indicates the process is working.
After 2-3 days, add water to fill the jar. Stir vigorously. Good seeds will sink; pulp, mould, and empty seeds will float.
Carefully pour off the floating debris. Repeat the fill-stir-pour process 2-3 times until the water runs mostly clear.
Tip the clean seeds into a fine mesh strainer. Rinse under running water.
Spread seeds in a single layer on a plate or paper towel. Label immediately with variety name and date.
Dry in a warm, well-ventilated area out of direct sunlight for 5-7 days. Seeds should snap cleanly when bent (not bend).
Store dried seeds in labelled envelopes in a cool, dry, dark place. Add a silica gel packet if available. Record the variety, source plant, date saved, and any selection notes in your seed library.