How To Save Tomato Seed

Bonny Best tomato

Tomato seeds are often gardeners' first foray into seed saving. If you've found a variety or two that you really like or that are hard to find, you may want to save some seeds to ensure they continue to be part of your garden. It is not difficult to save tomato seeds but there are a few important steps to the process.

First of all, you have hopefully planned for seed-saving when you planted your garden and have ensured that the varieties you want to save are sufficiently isolated from the rest of your tomato crops. “Sufficiently isolated” is a tricky and contentious term amongst tomato seed-savers: some people swear that they can grow different varieties of tomatoes side-by-side and have no cross-pollination; others advocate separating seed varieties by 150 ft or more. The key is the shape of the tomato flower. Although considered self-pollinating, tomato flowers can have their stigmas protruding past the anthers and, in these cases, they can be fairly easily cross-pollinated by insects visiting from plant to plant. To be safe, home gardeners saving seed just for themselves should distance the tomato varieties from which they intend to gather seed by at least 10 ft from other varieties.

Tomatoes are harvested for seed at the same time you would harvest them to eat – when they are fully ripe. Choose fruits that are most representative of the specific variety and harvest fruit from several plants to capture the best genetic profile. Next comes the fun part – fermentation! This removes the germination-inhibiting gel from around the seeds. It's a little messy and a little stinky, but increases germination substantially so it's well worth it.

Cut up ripe tomatoes into quarters and place them in a container. If you'd like to save the flesh for cooking, you can just squeeze the seeds and surrounding gel from the tomatoes into the container. Add enough cold water to cover the tomato mixture and stir well.

 Place the container in a cool, out of the way spot – you may want to put it in a really out of the way spot, as it does get quite smelly during the fermentation process. If desired, you can put a cloth over the container. Whatever you do, make sure you label the container with the name of the tomato, especially if you are saving seeds from more than one variety (they all look pretty similar when they're mashed up!). Over about three days, the tomato mixture will form a white, foamy “crust”; when the crust covers the entire container, your tomato mixture is ready for the next step.

Large jugs of tomato seed waiting to be cleaned

Skim off the crust and scoop out a lot of the tomato flesh that's at the top. Then pour most of the water out – the good seeds will have settled to the bottom. Add clean water and then pour that out. Continue to do this until all you have left is clear water with a layer of clean seeds at the bottom

. Pour off as much of the water as possible and put the seeds in a suitable place to dry. We have found that it's best to dry tomato seeds as quickly as possible or they'll start germinating – and as much as we appreciate their eagerness, they need to wait until the following spring! Dan's favourite method is to place the seeds in a plastic sieve and place the sieve in front of a fan. The fan, blowing at medium strength, should dry the seeds in a matter of hours. Do not use a metal sieve; it will blacken the seeds. This doesn't affect their viability but it makes them look ugly. You can also spread the seeds out in a single layer on a cookie sheet or plate – please don't use paper towel; the seeds will stick to it after they've dried and you'll have a devil of a time getting all those little bits of paper off.

When the seeds are completely dry, store them in a glass jar or paper seed envelope, label clearly, date and keep them in a cool, dark, dry environment until you're ready to plant next spring.