How to Store Tomato Seeds and for How Long?

Pick the seed tomatoes after they ripen completely on the vine. If you have to harvest the fruit prior to that point, set it on the counter at room temperature. Allow tomatoes to become overripe to ensure that the seeds are mature.

Cut the tomato in half. Scoop or squeeze the seeds and their surrounding gelatinous pulp into a glass jar. Leave the jar on the counter for several days at room temperature to allow the seeds and pulp to ferment for two or three days. This will make the seeds easier to remove from the pulp.

Add about 1 cup of water to the jar. The tomato seeds will sink to the bottom, leaving the pulp afloat. Slowly pour as much of the water and pulp from the jar as you can, without dumping any of the seeds out. Strain the seeds and remaining fluid through a coffee filter.

Spread the seeds out thinly in a single layer on several thicknesses of paper towels. Allow them to dry completely at room temperature.

Empty the dried tomato seeds into a paper envelope. Label the envelope clearly with the date and variety.

Cut an old pair of pantyhose off at the knee. Open a fresh package of powdered dry milk and pour about ½ cup of it into the hosiery. Tie a knot in it right above the milk and drop the sachet into a clean, dry glass jar.

Add the envelope of tomato seeds to the jar and cap it tightly. The powdered milk will act as a desiccant and absorb any remaining moisture and keep your seeds dry. Replace the milk every six months.

Refrigerate the jar of tomato seeds between 32 and 41 degrees Fahrenheit. They'll remain viable for about four or five years.