On Saturday, St. Thomas church played host to Spring FEASt Fest in St. John's, and I ran demos on how to save tomato seeds. Overall, I think it went very well; people seemed to respond pretty well to the demo, and I managed to swap for some seeds that I've had trouble finding. I also met Dan Rubin, who runs Perfectly Perennial Seeds & Herbs out in Pouch Cove. We had a great time chatting about saving seeds, and the importance of localizing varieties to the unique growing conditions here in Newfoundland. So, for those of you who couldn't make it, here's the gist of how you can save tomato seeds, and have them on hand for the next season.
First off, you'll need some tomatoes. I don't recommend trying to save the seeds from tomatoes that come from the grocery store, as most of them are hybrids. This means that any plants that come from those seeds will likely be one of the parent plants of the hybrid (at best) or won't sprout at all (at worst). Most tomatoes that are labelled as "heirloom" are fine, and if you grow your own tomatoes that are labelled "open pollinated", they should be fine as well, as long as the fruit is ripe. Next, you'll need some containers. I like using small glass jars, as it lets light in, and makes it easier to see what's going on. Plastic wrap is ideal for covering the tops of the jars, and you'll also need a sharp knife, a spoon, some sort of fine strainer, and paper towels.
Start off by cutting the tomatoes in half. I find that if you cut along the middle (that is, not down from where the stem joins the fruit), it's easier to get the seeds out. Using the spoon, scoop the gel and tomato seeds in to the jar. Don't throw away the scooped-out tomatoes, as you can roast them in the oven for a tasty treat! Add a little water - you should probably use filtered water, to ensure that there's no chlorine in it to contaminate the seeds - and stir the seeds, gel and water around in the jar. Cover the jar with plastic wrap, and poke a couple small holes with the knife, and put the jar somewhere warm. I've read that you shouldn't put it in direct sunlight, but I've always found that this works just fine. Stir the jars every couple of days, and let the mixture ferment for a couple of weeks. When it starts looking kind of gross (usually milky), and seeds are sitting on the bottom of the jar, you're ready to go.
Pour the mixture through your strainer, and rinse with non-chlorinated water to remove any remaining gel. Put the cleaned seeds on to some clean paper towel, and spread them out so that they can dry out evenly. Put the seeds somewhere sunny for a couple of weeks, until the seeds are COMPLETELY dry (they should feel like little flecks of paper when you handle them). If the seeds aren't dry, they can get mouldy, which usually renders them sterile. I like to put them in those little manilla coin envelopes, as paper does breathe a little. Remember, seeds may be dormant, but they're still living organisms.
You might be asking yourself, why don't I just dry the seeds straight out of the tomato? After all, this might sound like a lot of work! Well, it's slightly more work than beans or peas, but the results are well worth it, and most of the time is spent waiting - there's actually very little work. The reason that we have to take these extra steps is to roughly simulate what would happen to a tomato if left to its own devices in nature. The gel inside the tomato acts as a sprouting suppressant when it's fresh; once it has fermented and broken down, the seeds are viable and ready to sprout. If you think about what would happen in nature, the tomato ripens in August or September here, and if the seeds sprouted right away, the new seedlings would be killed off in the cold of the fall.
If you'd like to learn more about seed saving, I recommend checking out Seeds of Diversity. They're a not-for-profit organization dedicated to helping Canadians preserve our plant biodiversity. You can also check out this article on basic seed saving by Dan Rubin, it has a lot of great general info on seed saving and links to other resources.