Saving Seeds from Tomatoes

Editor's Notes

• #2: Welcome to the Seed Savers Exchange webinar series. [click]
• #4: Importance of saving seeds to maintain varieties after they are no longer commercially available. 408 different tomato varieties were offered in 1903, in 1983 only 79 of them are still extant.
• #5: Defining Heirlooms Seed Savers Exchange defines an heirloom as any garden plant that has a history of being passed down within a family, just like pieces of heirloom jewelry or furniture.
• #6: Seed saving is the process of saving seeds from open-pollinated fruits, vegetables, grains, flowers & herbs. Traditional agriculture relied on seed saving to maintain farms and gardens year after year. Today, many gardeners continue this tradition for a variety of reasons: reconnect with traditional agriculture reduce annual seed purchases maintain genetic diversity in the food system preserve rare or storied varieties As soon as you begin to think about preserving particular varieties, whether they be family heirlooms or commercial varieties that are no longer available, it is important to understand how to maintain that variety’s characteristics. [click] This type of preservation seed saving can be easily conceptualized by its goal: when you save seeds from a particular plant variety, you want those seeds to grow into a plant that is identical to its parent plants. This trait is known as varietal purity. So if I have a large red, ribbed tomato with excellent, sweet flesh, I want to be able to harvest the tomato, save the seeds, store them through the winter, plant them in the spring, and towards the end of the summer I want to be harvesting ribbed red tomatoes with excellent sweet flesh. Maintaining these characteristics is only possible with open-pollinated varieties. [click] An open-pollinated variety exhibits varietal purity and breeds true from seed. Open-pollinated varieties are maintained by allowing a natural flow of pollen between plants of the same variety. However… [click] When pollen flows between different varieties within the same species, this is known as cross-pollination. Cross-pollinated seed is not ideal for seed saving, and is worthless when you want to preserve a variety and its characteristics. If you are less concerned with maintaining the characteristics of a particular variety, cross-pollinated seed can still be saved and planted again in the spring, but you do not necessarily know what that plant will look or taste like. [click]
• #7: So, back to our red tomato. [click] Lets say that I’ve planted a mild, orange, cherry tomato right next to my large, ribbed red tomato. [click] If a bee were to move pollen from one variety to another, the seed produced could grow into a plant that exhibits traits of both varieties – maybe we’d end up with a medium-sized, orange, lightly-ribbed tomato with a mild flavor. This might be acceptable if you’re only interested in seed saving to cut down on your garden budget, but if you’re interested in perpetuating a variety that maintains its characteristics year after year, you must take steps to prevent cross pollination. [click]
• #8: Which varieties can you save seed from? Saving your own seeds requires open-pollinated varieties rather than hybrids.
• #9: Tomatoes are self-pollinating and grown as annuals in much of the United States. They produce seed within the first year of their life, and for many varieties, their flowers are designed in such a way that pollen does not readily flow between plants. The flowering phase of a plant’s lifecycle is one of the most crucial for seed savers to know and understand. Self-pollinating plants, like tomatoes, beans, and lettuce, produce ‘perfect’ flowers. This means that each flower contains both male and female parts – the male part of the flower produces pollen, and the female part of the flower accepts that pollen and develops into a seed. This process is known as fertilization. Because there is a source of pollen so close to the pollen receptor, fertilization generally happens before pollen from a different plant has a chance to be transferred. Many tomato varieties have flowers which completely enclose the female pollen receptor with a contamination-shielding cone of pollen-producing anthers, which makes cross pollination highly unlikely. A quick note regarding self-pollination: just because a plant is inclined to self-pollinate does not mean that cross-pollination is impossible. Wind and insects can move pollen around and potentially contaminate varieties with stray pollen. Because of this, we recommend that seed-savers do not grow varieties side by side. If you are only growing two varieties of beans, for example, put them at either end of the garden to reduce the chance of cross-pollination. After fertilization, seeds develop. Seed development can be seen easily in beans as bean pods grow and the seeds inside become more defined. Tomatoes enclose seeds within their fruit. [click]
• #11: As we talk about seed production and harvest, it is important to think about the health and diversity of your plants. Seeds should only be saved from healthy plants, and healthy plants require healthy soil. Just because your plants may be grown for seed does not mean that they require any less care than plants you grow for food – in fact, for the health and vigor of your future gardens, it is even more important that the seed you save represent your most robust plants. Maintaining healthy plants could be a whole separate webinar, but there are a few things to remember: keep your soil fertile inhibit the spread of diseases control harmful insects and other pests If your plants are healthy, your seed should be as well. Seed health affects germination rates as well as plant vigor in the next generation. To further ensure the health of future plant generations, you should save seeds from a number of different plants within a particular variety. For self-pollinating plants like tomatoes, a population of 20 individual plants would be ideal. Of course, space restrictions can be a major limiting factor with regard to population size – not every gardener has room to grow 20 tomato plants of the same variety, and if you’d like to save seeds from two or three varieties, very few gardeners have space for 40 to 60 tomato plants in addition to all of the other fruits and vegetables they’d like to grow. A more realistic guideline might be that seed savers should simply grow as many plants as they can in the space they have. Saving seeds from several plants of the same variety ensures a more resilient plant population in the future. If you only save lettuce seeds from a single plant, all of your future plantings will have the exact same strengths and weaknesses of its parent. Perhaps a particular plant bolted extremely early; it is likely that any plants grown from that parent’s seed would also bolt extremely early – a somewhat undesirable characteristic if you want to be able to harvest lettuce for salads into the summer. By saving seeds from many different plants, you keep your population genetically diverse and avoid undesirable ‘bottlenecks’ such as late maturation, susceptibility to diseases, etc. On the other hand, you may find that one of the lettuce plants you’ve grown does not match any of the other plants within that variety. If you are saving seed in order to preserve a particular variety and its characteristics, it is important to rouge out any plants that are off-type, or dissimilar from the other plants in your population. If you have a potato-leafed plant among 20 regular-leafed tomatoes, remove it from the garden, preferably before it flowers, and do not save seed from that particular plant. [click]
• #12: Tomato Seed Saving Overview
• #13: Tomato seeds are ready for harvest when the fruits are ripe, but leave the fruits on the vine until they are past their prime. Famed tomato seedsman Ben Quisenberry suggested waiting until the fruits were partly rotten so that the plant could put as much energy as possible into the development of the seed. Harvest over-ripe fruit from the healthiest plants in your garden – don’t just harvest the biggest, brightest fruits, but harvest a range of fruits that all basically exhibit the same characteristics and represent healthy plants. [click] To remove tomato seeds from their fruit, cut the fruit in half across the middle. This exposes a large seed cavity and makes the seeds accessible without mashing the fruit. Scoop or squeeze out the seeds and place them in a tall container. There will be a lot of extra ‘pulp’ or gel from the fruit along with the seeds. [click] Tomato seeds should be left to ferment in the container with the pulp and a bit of added water for a few days. This breaks down a coating that prevents tomato seeds from germinating too early. Be warned that fermenting tomatoes do not have a pleasant scent… [click] When a layer of mold develops on the surface of the seed/pulp/water mixture, you can stop the fermentation process. Add enough water to double the mixture and stir it vigorously. The good seeds will settle to the bottom of the container, allowing the mold and debris and hollow seeds to be poured off. Add more water and repeat the process until only clean seeds remain. [click] Pour the clean seeds into a strainer, then dump the seeds onto a ceramic dish or coffee filter to dry. Spread them out as much as possible to increase air flow and the rate at which they dry. Stir the seeds around once or twice a day as they dry in an airy location out of direct sunlight. [click] Tomato seeds are dry enough for storage when they break rather than bend under stress. Try to bend a couple of your tomato seeds – they should ‘snap’ if they are suffiently dry. If they bend, continue drying them. [click]
• #16: Tomato seeds are ready for harvest when the fruits are ripe, but leave the fruits on the vine until they are past their prime. Famed tomato seedsman Ben Quisenberry suggested waiting until the fruits were partly rotten so that the plant could put as much energy as possible into the development of the seed. Harvest over-ripe fruit from the healthiest plants in your garden – don’t just harvest the biggest, brightest fruits, but harvest a range of fruits that all basically exhibit the same characteristics and represent healthy plants. [click] To remove tomato seeds from their fruit, cut the fruit in half across the middle. This exposes a large seed cavity and makes the seeds accessible without mashing the fruit. Scoop or squeeze out the seeds and place them in a tall container. There will be a lot of extra ‘pulp’ or gel from the fruit along with the seeds. [click] Tomato seeds should be left to ferment in the container with the pulp and a bit of added water for a few days. This breaks down a coating that prevents tomato seeds from germinating too early. Be warned that fermenting tomatoes do not have a pleasant scent… [click] When a layer of mold develops on the surface of the seed/pulp/water mixture, you can stop the fermentation process. Add enough water to double the mixture and stir it vigorously. The good seeds will settle to the bottom of the container, allowing the mold and debris and hollow seeds to be poured off. Add more water and repeat the process until only clean seeds remain. [click] Pour the clean seeds into a strainer, then dump the seeds onto a ceramic dish or coffee filter to dry. Spread them out as much as possible to increase air flow and the rate at which they dry. Stir the seeds around once or twice a day as they dry in an airy location out of direct sunlight. [click] Tomato seeds are dry enough for storage when they break rather than bend under stress. Try to bend a couple of your tomato seeds – they should ‘snap’ if they are suffiently dry. If they bend, continue drying them. [click]
• #20: Tomato seeds are ready for harvest when the fruits are ripe, but leave the fruits on the vine until they are past their prime. Famed tomato seedsman Ben Quisenberry suggested waiting until the fruits were partly rotten so that the plant could put as much energy as possible into the development of the seed. Harvest over-ripe fruit from the healthiest plants in your garden – don’t just harvest the biggest, brightest fruits, but harvest a range of fruits that all basically exhibit the same characteristics and represent healthy plants. [click] To remove tomato seeds from their fruit, cut the fruit in half across the middle. This exposes a large seed cavity and makes the seeds accessible without mashing the fruit. Scoop or squeeze out the seeds and place them in a tall container. There will be a lot of extra ‘pulp’ or gel from the fruit along with the seeds. [click] Tomato seeds should be left to ferment in the container with the pulp and a bit of added water for a few days. This breaks down a coating that prevents tomato seeds from germinating too early. Be warned that fermenting tomatoes do not have a pleasant scent… [click] When a layer of mold develops on the surface of the seed/pulp/water mixture, you can stop the fermentation process. Add enough water to double the mixture and stir it vigorously. The good seeds will settle to the bottom of the container, allowing the mold and debris and hollow seeds to be poured off. Add more water and repeat the process until only clean seeds remain. [click] Pour the clean seeds into a strainer, then dump the seeds onto a ceramic dish or coffee filter to dry. Spread them out as much as possible to increase air flow and the rate at which they dry. Stir the seeds around once or twice a day as they dry in an airy location out of direct sunlight. [click] Tomato seeds are dry enough for storage when they break rather than bend under stress. Try to bend a couple of your tomato seeds – they should ‘snap’ if they are suffiently dry. If they bend, continue drying them. [click]
• #22: Now you wait for the magic to happen! If you can, stir your mash daily. The mixing will actually deter any mold/fungus from forming on the top (which is actually a good thing) and will ensure that all seeds interact equally with the yeasts to allow for even fermentation.  This process also helps release the released seed so it can sink to the bottom of your container.  Too much of that fungal formation on top can lead to other seed problems like discoloration (darkening of the seed) and has potential to damage the embryo--what you want to rely on more to indicate that fermentation is complete is that when you agitate the solution, and mix the seeds all around, that the majority of seeds are falling to the bottom of your holding container.  For this reason, it is really nice to be able to ferment seeds in a see-through container. This will indicate to you that the jelly coating surrounding those seeds has been adequately removed and the fermentation is complete.  I generally would not recommend that seeds be left sitting to ferment for any longer than 3 days.  Temperature and amount of water added are two factors that will influence the fermentation time. About 70 degrees F, or slightly warmer, is ideal for this to occur (2-3 days).  Extremes in either direction (+/- 15-20 degrees) can potentially cause seed damage.
• #24: Tomato seeds are ready for harvest when the fruits are ripe, but leave the fruits on the vine until they are past their prime. Famed tomato seedsman Ben Quisenberry suggested waiting until the fruits were partly rotten so that the plant could put as much energy as possible into the development of the seed. Harvest over-ripe fruit from the healthiest plants in your garden – don’t just harvest the biggest, brightest fruits, but harvest a range of fruits that all basically exhibit the same characteristics and represent healthy plants. [click] To remove tomato seeds from their fruit, cut the fruit in half across the middle. This exposes a large seed cavity and makes the seeds accessible without mashing the fruit. Scoop or squeeze out the seeds and place them in a tall container. There will be a lot of extra ‘pulp’ or gel from the fruit along with the seeds. [click] Tomato seeds should be left to ferment in the container with the pulp and a bit of added water for a few days. This breaks down a coating that prevents tomato seeds from germinating too early. Be warned that fermenting tomatoes do not have a pleasant scent… [click] When a layer of mold develops on the surface of the seed/pulp/water mixture, you can stop the fermentation process. Add enough water to double the mixture and stir it vigorously. The good seeds will settle to the bottom of the container, allowing the mold and debris and hollow seeds to be poured off. Add more water and repeat the process until only clean seeds remain. [click] Pour the clean seeds into a strainer, then dump the seeds onto a ceramic dish or coffee filter to dry. Spread them out as much as possible to increase air flow and the rate at which they dry. Stir the seeds around once or twice a day as they dry in an airy location out of direct sunlight. [click] Tomato seeds are dry enough for storage when they break rather than bend under stress. Try to bend a couple of your tomato seeds – they should ‘snap’ if they are suffiently dry. If they bend, continue drying them. [click]
• #32: Tomato seeds are ready for harvest when the fruits are ripe, but leave the fruits on the vine until they are past their prime. Famed tomato seedsman Ben Quisenberry suggested waiting until the fruits were partly rotten so that the plant could put as much energy as possible into the development of the seed. Harvest over-ripe fruit from the healthiest plants in your garden – don’t just harvest the biggest, brightest fruits, but harvest a range of fruits that all basically exhibit the same characteristics and represent healthy plants. [click] To remove tomato seeds from their fruit, cut the fruit in half across the middle. This exposes a large seed cavity and makes the seeds accessible without mashing the fruit. Scoop or squeeze out the seeds and place them in a tall container. There will be a lot of extra ‘pulp’ or gel from the fruit along with the seeds. [click] Tomato seeds should be left to ferment in the container with the pulp and a bit of added water for a few days. This breaks down a coating that prevents tomato seeds from germinating too early. Be warned that fermenting tomatoes do not have a pleasant scent… [click] When a layer of mold develops on the surface of the seed/pulp/water mixture, you can stop the fermentation process. Add enough water to double the mixture and stir it vigorously. The good seeds will settle to the bottom of the container, allowing the mold and debris and hollow seeds to be poured off. Add more water and repeat the process until only clean seeds remain. [click] Pour the clean seeds into a strainer, then dump the seeds onto a ceramic dish or coffee filter to dry. Spread them out as much as possible to increase air flow and the rate at which they dry. Stir the seeds around once or twice a day as they dry in an airy location out of direct sunlight. [click] Tomato seeds are dry enough for storage when they break rather than bend under stress. Try to bend a couple of your tomato seeds – they should ‘snap’ if they are suffiently dry. If they bend, continue drying them. [click]
• #36: We’ll end the presentation by talking briefly about seed storage. The photo on the screen shows one of the freezers here at Heritage Farm used for long-term seed storage. Obviously, home gardeners do not have this type of facility, but neither do home gardeners require the same type of long-term preservation storage that we do. It is helpful to remember that seeds contain embryonic plants that are just waiting for the right conditions to germinate and grow. Most garden plants require moisture, oxygen, and warm temperatures to begin this process. Ideal conditions for storage, then, should deprive seeds of these three things, particularly moisture. Seeds should be dried thoroughly before storage – passing the ‘break’ or ‘shatter’ tests described previously. If your seeds have been sufficiently dried, store them in an air-tight container and place them in a cool, dry location. Cooler temperatures slow the metabolism of the embryonic plants, allowing them to be stored longer. It is not recommended to store your seeds in a refrigerator, however, which is generally too moist. Some home gardeners will try to store their seeds in the freezer, but this is not necessary for home gardeners planning to grow out their saved seeds within a couple years. It can also be harmful to seeds, as even a little moisture inside the seed can freeze, expand, and rupture the embryo. Later this year, we will be presenting a separate webinar on seed storage in order to cover additional plant types and further illustrate the principles we’ve introduced here, which I would encourage you to attend! [click]
• #38: That covers the basics of seed saving related to tomatoes. Hopefully you’ve learned enough to consider your own small-scale seed saving project in the future. Thank you very much for your attendance, and we will now take some time to answer questions.