When the summer is waning and the tomatoes are beginning to taper off, it is time for a consummate gardener to begin thinking ahead to next summer’s bounty already. If you have a garden full of heirloom tomatoes that you would like to taste again next summer, consider saving these seeds for next season. With only a bit of time and effort, you can harvest enough tomato seeds to plant in next season’s garden.
Select heirloom tomatoes for saving seeds. Hybrid tomato varieties do not possess the same properties and may not produce reliable tomatoes in future seasons.
Cut ripe tomatoes in half between the top and bottom of the tomatoes. Squeeze the insides of the tomato halves into the plastic containers and discard the outside of the tomatoes. Label the plastic containers with the black marker so you know what tomato variety is in each container.
Place the lids loosely onto the containers (do not seal tightly) and place the containers in a warm place out of direct sun.
Wait between one and three days for fermentation to occur. The viable seeds will sink to the bottom of the containers and the material to discard will rise to the top.
Pour the materials on the top of the containers down the sink, being careful not to pour out the tomato seeds at the bottom of the container. Pour the remaining seeds into the metal strainer.
Place the metal strainer in the sink and run cold water over the seeds. Rinse the seeds to remove the undesired material from the good seeds.
Pour the remaining seeds into the center of a coffee filter and spread them out into a single layer on the filter. Label the filter with the type of tomato seeds.
Place the coffee filter in a location that is warm, has adequate ventilation and is out of direct sun. Rearrange the seeds several times each day to promote drying. Wait for approximately one week until the seeds are completely dry. Store the seeds in sealed, glass jars in a cool location for up to 10 years.