1.Choose a ripe, perfect tomato.
2.Cut it across the center of the fruit.
3.Squeeze the seeds, gel, and juice out into a small cup or jar.
4.Cover the seed gunk with two to three inches of water.
5.Label your container so you know which variety of tomato you saved seeds from.
6.Set the labeled jar in an out-of-the way spot and wait.
7.After about three days, white mold will start to form on the surface of the water. This means that the gelatinous coating on the seeds has dissolved.
8.Once you see the white mold, pour off the mold, the water, and any seeds that are floating (floating seeds are bad - they wouldn't have germinated.) You want all of those seeds sitting at the bottom of the cup.
9.After you've poured the mold and bad seeds off, drain your seeds in a fine mesh strainer and rinse under running water. It's not a bad idea to move the seeds around with your fingers to remove any extra gel that may be clinging to them.
10.Dump your rinsed seeds onto a paper plate that has been labeled with the variety name. (Yes, paper plates. Not ceramic. You need something that will wick the water away from the seeds so they dry fast and don't get moldy.)
11.Make sure your seeds are in a single layer on the plate, and set it aside a few days so the seeds can completely dry.
12.Once they're dry, put them in a labeled envelope, baggie, or other container and store in a cool, dry spot. I like to keep mine in the fridge.
Tomato seeds will keep well and germinate reliably for up to ten years if stored properly.
So, there you have it. Save seeds from your favorite tomatoes, and grow them every year. You'll be helping to protect genetic diversity in our food supply and keep some great heirloom tomatoes growing. And you'll be rewarded each and every time you enjoy a ripe, juicy tomato straight from your own garden.