How to save your tomato seeds:
Housed in a juicy fruit, tomato seeds need a special strategy to keep from germinating too soon. The seeds have a protective coating that is dissolved by the enzymatic action of molds in rotten fruit. Pick out your most perfect, very ripe tomatoes. Scoop seeds and the gelatinous goop around them into a container and set the mess aside until the top is covered with mold (usually two or three days, depending on temperatures). Then rinse well and dry the seeds on a screen or wax paper.