Saving Tomato Seed

By Nina Berryman

During U-Pick the other day, one of the shareholders asked me a few questions about how to save tomato seed. Saving seed is a great way to increase your self-sufficiency, select for traits that are specifically adapted to your unique growing area, save money, and connect with your food in yet another way. When you save seed from a tomato, you are most likely going to get the seeds that produce a plant that grows tomatoes just like the one the seeds came from. In other words, the plants do not cross-pollinate and the seeds will be true to their parent plant. This is true most of the time. There are a few varieties of tomato that do not produce seeds that yield the same types of fruit. Those are potato-leaved varieties (such as the popular brandywine variety), currant tomatoes and any fruit formed from double blossoms of beefsteak tomatoes.
The following paragraphs are selected from one of my favorite farming resources, “Seed to Seed” by Suzanne Ashworth.

Pick and wash fully ripe tomatoes, and then cut the fruits across the middle, not through the stem and blossom ends. This exposes the large seed cavities and makes the seeds accessible without smashing the fruit. Now squeeze the seeds and surrounding gel into a bowl or bucket.
Each tomato seed is encased in a gelatinous sack. The gel in these sacks contains chemicals that inhibit sprouting inside the wet flesh of the tomato. In nature the ripe tomatoes fall from the plant and destroyed. Eventually the fruits totally rot away leaving the seeds on the surface of the soil, ready to germinate when conditions are right.
Artificially duplicating the tomato fruit’s fermentation process is not difficult. In addition to removing the gel sack, fermentation also kills many seed-borne diseases.
The container of tomato seeds and gel should be set aside to ferment to one to three days. Fermentation will proceed more quickly as the daytime temperatures increase.
During this period the container of seeds will begin to stink and will become covered with a layer of white or gray mold. Because of the horrible smell, do not keep the bowl in the house or where it might be tipped over by animals or children. The fermentation process should be stopped when the layer of mold completely covers its surface. Be sure to monitor the process closely because, if allowed to continue too long, the seeds will begin to germinate in the mixture.
Add enough water to double the mixture and then stir it vigorously. The good seeds will settle to the bottom of the container, allowing the mold and debris and hollow seeds to be poured off. Add more water and repeat the process until only clean seeds remain.
Some growers prefer to pour the entire contents of the container into a strainer, without adding any water, and then wash under running water. Make a fist and use the fronts of your fingers to rub the mold and softened debris through the screen. Wipe the bottom of the strainer on a towel to remove as much moisture as possible and dump the seeds out to a glass or ceramic dish to dry. Do not attempt to dry the seeds on soft paper or cloth or non-rigid plastic, as it is extremely difficult to remove the seeds from these surfaces. Coffee filters, which are inexpensive to purchase reportedly work well and tend to wick the moisture away from the seeds during drying.
To ensure even drying and to prevent the seeds from bunching together, stir at least twice a day. Never dry seeds in direct sunlight or in an oven. Tomato seeds will begin to germinate if not dried quickly. In hot humid weather, a fan will help speed the drying process.