Saving seeds from your vegetable plants gives you access to viable seed without the expense of purchasing new seed stock each year. Tomatoes are commonly grown in the home garden and their seeds are simple to save with just a small amount of planning. Tomato seeds are encased in a gel-like pulp that must be washed away before you can store them. Otherwise, the moisture in the pulp causes the seeds to rot. Extracting the tomato seeds takes little effort but some time.
Pick fully ripened tomatoes from a healthy plant in your garden. Harvest the tomatoes when they are at their full color and when they feel slightly overripe.
Cut the tomato in half with a sharp knife. Squeeze out the pulp and seeds into a bowl or a glass. Leave the seeds and pulp to ferment at room temperature for two to three days.
Fill the bowl or glass with lukewarm water once the seeds have sunk to the bottom of the bowl. Pour off the water and pulp, leaving the seeds in the bottom of the bowl.
Spread the seeds out on a paper towel and set them in a dry room for one week. Replace the paper towel if it becomes damp during the drying time.
Label a jar or envelope with tomato variety and the year harvested. Pour the dried seeds into the envelope and store in a cool, dry place until you are ready to plant.