Tomato aficionados are such thrill seekers.
With hundreds of different varieties available in the Bay Area as seedlings, why would anyone want to spend an extra couple months to grow tomatoes from seed?
Because you can. Because thousands of varieties of tomatoes are available from seed, so you need purchase seed only once. And because, if you know the right people, you can obtain varieties that aren't yet available commercially, and keep growing them yourself.
I've been growing heirloom tomatoes for years, but last year was the first time I saved seeds.
The basics are easy. First, choose an open-pollinated (OP) variety that you like. Some common OP varieties are Cherokee Purple, Brandywine, Black Cherry, Pineapple, and Caspian Pink. These are all varieties that, collected properly, will breed true.
You can, of course, save seeds of hybrid tomatoes, but you can't count on getting anything resembling the parent tomato if you plant the seeds. Hybrids include SunGold, Momotaro, and Russo Bruno.
Second, collect them properly. Tomatoes are self-pollinating – and you can facilitate pollination by shaking the tomato cages whenever you pass by! – but bees in your garden will collect pollen from your tomatoes and, in the process, sometimes cross-pollinate them. Bee activity won't affect this year's crop, but if you want to be absolutely sure your seeds breed true, you need to bag your blossoms.
The bags can be made of any material that allows light and air through, but keeps tiny pollinators out. You can buy organza bags, or make bags from nylon stockings or other fabric. Each bag should be big enough to enclose a blossom truss, with a way to tie the end that holds it to the stem. As soon as you see a bunch of tomato blooms forming, but before they open, place a bag over the blossoms. Keep it in place until the green fruits start forming, and then tie a ribbon to that stem so you'll remember which tomatoes were bagged.
Cross-fertilization is rare unless you're growing one of the currant tomatoes, however. You can generally skip the bagging step if you collect seeds from your earliest tomatoes, which may have developed before bees were out in numbers, or if you're willing to take a chance. I've also collected seeds from identified farmers' market tomatoes.
Third, when your chosen tomato is ripe, squeeze the seeds and juice into a labeled pint or quart container, and add another inch or so of water. (You can eat the rest of the tomato.) Use a different container for each tomato variety. Let it sit outdoors for at least 5 days to ferment. It will get moldy and stinky, which is good. The fermentation helps break down the gelatinous coat around each seed, and reduces the chance of passing on any diseases from this year's garden.
Fourth, when a layer of mold has formed, take your hose-end sprayer and gently fill the container. Pour off the mold, being careful not to pour out the seeds at the bottom. Any seeds that float can be discarded. Continue to rinse.
Fifth, when the water runs clear, put the seeds on a clean piece of paper to dry, marked with the tomato's name. Separate the seeds so they don't clump and sprout prematurely.
Sixth, after the seeds have dried – at least a week – store them in labeled envelopes in a cool, dry place. Well stored seeds will be viable for at least 5 years.
Some great sources of OP tomato seeds are Sandhill Preservation, Tomato Growers Supply, and Victory Seeds. A wonderful book to aid selection is 100 Heirloom Tomatoes for the American Garden by Carolyn Male.
© 2009 Tanya Kucak