TOMATOESANDCUCUMBERS have seeds that are coated with a gel containing antigermination compounds. The gel must be removed by fermentation to Tomatoessuccessfully save these seeds. In addition to removing the gel, fermentation kills many seedborne pathogens, ensuring disease-free seeds. The process smells bad, however, so don’t do it in an enclosed room in the house.
Follow these steps:
Squeeze or spoon the seed mass into a waterproof container. I like clear-plastic throwaway cups, but a jar, water glass, or deli container will do.
Add enough water to equal the volume of the seed mass, and put the container in a warm spot out of direct sunlight.
Stir the contents at least once a day.
In a couple of days, the fermentation process will have started. Viable seeds will sink to the bottom, and bad seeds, debris from the seed mass, and a white mold will float on the surface.
When all the good seeds have dropped (which takes about five days), rinse away the gunk on top. Wash the seeds in several changes of water, and lay them out in a single layer on a glass or plastic plate or screen.
Put the plate in a warm place until the seeds are fully dry, which can take several weeks.