In late summer, you can take advantage of the last ripe fruits to obtain your own tomato seeds. Here is how to do it and how to properly store them afterwards.
If you want to obtain your own tomato seeds, you must first check whether the tomatoes you grow are suitable for seeds at all. Many varieties offered in the gardening trade are so-called F1 hybrids. These are varieties that have been crossed from two so-called inbred lines with precisely defined characteristics in order to obtain tomato seeds. The F1 varieties created in this way are very efficient due to the so-called heterosis effect, because the positive characteristics anchored in the parental genetic material can be specifically recombined in the F1 generation.
F1 varieties, however, cannot be propagated true to variety from their own tomato seeds: In the second generation, in genetics this is called F2, the characteristics typical of the variety are very differently and are largely lost again. This breeding process, also known as hybridization, is costly, but for the breeders it also has the great advantage that the tomato varieties produced in this way cannot be reproduced in their own gardens, so they can sell new tomato seeds every year.
Choose seed-stable tomato varieties
On the other hand, there are the so-called seed-stable tomato varieties. These are mostly old tomato varieties that have been cultivated over generations from their own seeds. This is where the oldest breeding method in the world comes into play: so-called selection breeding. One simply collects the tomato seeds of the plants with the best characteristics and propagates them onwards. A well-known representative of these reproducible tomato varieties is the flesh tomato ‘Oxheart’. Corresponding seeds are usually offered as organic seeds in garden specialty stores, since F1 varieties are usually not permitted in organic agriculture. However, the seed is also only suitable for replanting if, for example, you cultivate only this one tomato variety in a closed greenhouse. If your oxheart tomato was pollinated with the pollen of a cocktail tomato, the regrowth will probably also differ considerably from your expectations.
Obtain tomato seeds: Step by step
To obtain tomato seeds for the new year, as a rule, the seeds of a single well-matured fruit is enough. In any case, choose a plant that was very productive and also still produced particularly tasty tomatoes.
Cut tomatoes in half
Cut the selected tomatoes lengthwise.
Extract the pulp
Using a teaspoon, scrape out the seeds from the inside along with the mass surrounding them. Work best directly over a kitchen sieve, so that possible falling tomato seeds can land directly in it and are not lost.
Remove coarse remnants of pulp
Remove adherent or coarse remnants of the tomato with a spoon.
Rinse seeds thoroughly with water
After that, the seeds must first be thoroughly rinsed with water. By the way, rinsing under a faucet works even better than with a bottle.
Get seeds from the sieve
Get the rinsed seeds out of the sieve. They are still surrounded by a germination-inhibiting slimy layer. This causes somewhat delayed or irregular germination the next year.
Fermentation breaks down substances that inhibit germination.
Put the tomato seeds released from the fruit, together with the gelatinous mass surrounding them, in a bowl. Add some lukewarm water and let the mixture stand in a warm place for ten hours. Then stir the mixture of water and tomato mass with a hand mixer for one or two minutes at the highest speed and let the mixture rest for another ten hours.
Next, pour the seed mixture into a fine-mesh household strainer and rinse under running water. If necessary, you can help mechanically with a pastry brush. The tomato seeds can be separated very well from the rest of the mass and remain in the sieve. They are now removed, spread out on a paper kitchen towel and dried thoroughly.
How to store tomato seeds properly?
Once the tomato seeds are completely dry, put them in a clean, dry jam jar and store them in a cool, dark place until the tomatoes are ready to be sown. Tomato seeds can be stored for quite a long time, depending on the variety, and still show a very good germination rate even after five years.
Obtain tomato seeds: The fast way
If this is too much work for you, you can also add the seeds with the pulp on a kitchen paper and let them dry. Only choose the same seeds on one paper. After drying, simply write the name of the variety on it, fold the paper and store in a dry and dark place, best in a jar or container. Maybe not every seed will germinate, but the question is, how many plants do you really need?
Another advantage. You can simply loose the seeds or just cut little parts of the kitchen paper with a few seeds and palce this directly into your growing pot in the soil. The paper will rot and the seeds will grow.