Tomato seed collection and storage can reduce the cost of planting tomatoes in subsequent years, and it provides you the opportunity to reproduce your favorite tomato plants. Tomatoes from hybrid plant varieties may contain sterile seeds, and their viable seeds will produce unpredictable plant characteristics, so it's usually best to save tomato seeds from heirloom or open-pollinated varieties. Suitable tomato varieties include Brandywine, Green Zebra, San Marzano and Big Rainbow. Save your tomato seeds for up to five years.
Select a ripe, unblemished tomato for its seeds. Choose from a healthy plant with favorable characteristics if picking your tomato directly from the plant.
Slice the tomato in half or in quarters, and scoop the gelatinous seed filling into a small glass container.
Add approximately 1 tsp. of water to the container--more if the juice and water is not enough to cover the seeds.
Stir the seed mixture twice daily for three to five days. Fermentation will separate the tomato seeds from their gelatinous coating, and the top layer of the mixture may grow mold during this process.
Remove the layer of mold and residue from the container after fermentation completes; the tomato seeds will be resting at the bottom of the container.
Rinse the seeds with water, and set them in a single layer on paper towels. Allow them to dry thoroughly before storage; a few days at room temperature is generally sufficient.
Pour the seeds into an envelope labeled with the date and plant variety, and store them in the refrigerator or a dry, cool area.