OK, are you ready for some fun? Saving tomato seeds is not as quick and clean as saving most other kinds of seed. The secret to successful tomato seed-saving is fermentation, which takes time and can be quite, shall we say, aromatic.
Begin by choosing a very good-looking fully ripe fruit from your best, healthiest plant. (Remember to use only nonhybrid varieties.) Then cut the fruit in half through its “equator” (separating the top and the bottom). Scoop out all the gel and seeds and put the whole goopy mess into a bowl or glass jar. Go ahead and eat the rest of the tomato.
If the seeds aren’t floating at the top of the gel-and-seed goo, add a little water, anywhere from a couple tablespoons to a half cup or so. Cover the bowl or jar with cheesecloth or a paper towel. Then place the container in a warm spot, preferably where you won’t mind getting an occasional whiff of fermenting tomato goo. Let the stuff do its thing for 2-4 days.
At the end of the fermentation, the seeds will have sunk to the bottom of the container and the liquid will be covered with a lovely scum of gel and mold. Remove the scum skin and toss it, then drain off as much of the upper liquid as you can without pouring out any of the seeds. Separate the seeds from the remaining liquid by pouring what’s left into a fine sieve. Rinse the seeds in the sieve with warm water to clean the seeds completely.
Once the seeds are cleaned off, spread them on a paper plate. Put the plate in a warm, dry place. Shake the plate or stir the seeds every couple days to help the seeds dry evenly. After about a week – or more, if it’s humid – the seeds should be thoroughly dry. Put the dry seed in an envelope or glass jar, and store in a cool, dry place.
Phew!!! That’s a lot more involved then shaking dry chive seeds from a chive blossom, but that effort will be well worth it next year when you want to grow that heirloom tomato that’s been in your family for generations. 🙂