Saving tomato seeds from your best plants is easy to do. Seeds saved from heirloom varieties are best to use. Seeds from hybrids will not grow true to the fruits of the previous season. Heirloom tomatoes are those that are open pollinated and have not been hybridized. They have properties that can be traced back many generations. The age of the cultivar used to define “heirloom" status is open to some discussion, but is generally regarded to mean cultivars that existed before World War II due to the fact that hybrid varieties came into popular use for commercial tomato and seed production following the war.
To start choose the fruits with the most desirable traits. Cut the top of the tomato about ¼ way down and gently remove the seeds, save the remaining tomato and make a quick, fresh marinara sauce, stuffed tomato or add it to your salad. Tomato seeds are covered with a gelatinous coating that needs to be removed. This coating inhibits growth so that the seeds don't start sprouting inside the fruit. The best way to remove this coating is to follow nature's cue. When tomato fruits fall from the plant, they ferment as part of the decomposition process, and this removes the coating. To mimic this process you can place the seeds in a container containing water for 3-4 days.
Leave the container on your kitchen counter or someplace else warm, but out of direct sunlight. After three days, the surface of the liquid will be covered in foam from the fermentation and most seed will settle to the bottom of the container. Pour off the liquid and any floating seeds and rinse them gently. Place them on a non-porous surface to dry, out of direct sunlight. A fan can be used to hasten the drying process, but do not use a heated air source such as a hair dryer. When the seeds are thoroughly dry, place them in an airtight container and label the container with the variety name and date. Store the container in a cool, dry place. Tomato seeds are very durable and will last for several years as long as you make sure that the seeds are thoroughly dry before storing them.
Seed saving can turn into an interesting side hobby to gardening. There are many seed exchange programs where gardeners exchange the seeds that they have saved with other gardening enthusiasts. These groups help to maintain the diversity of plant life and provide a social outlet where gardeners can develop friendships with other gardeners across the country and across the world.
Neal and Cathy Klabunde are the owners of http://www.gardening-at-the-crossroads.com a gardening website for gardeners of all skill levels.