In late summer you can use the last ripe fruit to obtain your own tomato seeds. Here we show you how to do it and how to store it properly afterwards.
If you want to win your own tomato seeds, you first have to check whether the grown tomatoes are even suitable for seed production. Many of the varieties offered in gardening stores are so-called F1 hybrids. These are varieties that have been crossed to obtain tomato seeds from two so-called inbred lines with precisely defined properties. The F1 varieties produced in this way are very powerful due to the so-called heterosis effect, because the positive properties anchored in the parental genome can be combined in a targeted manner in the F1 generation.
However, F1 varieties cannot be propagated from their own tomato seeds according to variety: The varietal characteristics are different in the second generation – in genetics they are called F2 – and are largely lost again. This breeding process, also known as hybridization, is complex, but it also has the great advantage for the breeders that the tomato varieties produced in this way cannot be reproduced in their own garden – they can therefore sell new tomato seeds every year.
Seed-proof tomato varieties
In contrast, there are the so-called seed-resistant tomato varieties. These are mostly old tomato varieties that have been grown over generations from their own seeds. The oldest breeding method in the world is used here: the so-called selection breeding. You simply collect the tomato seeds of the plants with the best properties and multiply them further. A well-known representative of these cultivable tomato varieties is the meat tomato ‘ox heart’. Corresponding seeds are usually offered as organic seeds in gardening shops, since F1 varieties are generally not permitted in organic farming. However, the seeds are only suitable for replication if, for example, you only cultivate this one tomato variety in a closed greenhouse. If your ox heart tomato has been dusted with the pollen of a cocktail tomato, the offspring will probably also deviate significantly from your ideas.
This is how tomato seeds can be obtained and stored
So much for theory – now for practice: To get tomato seeds for the New Year, the seeds of one well-ripened fruit are usually enough. In any case, choose a plant that was very productive and also produced particularly tasty tomatoes.
Cut the selected tomatoes lengthways and use a teaspoon to scrape out the seeds together with the surrounding mass. It is best to work directly over a kitchen strainer so that possible falling tomato seeds can land directly in them and are not lost.
Use a spoon to remove adhering or rough remnants of the tomato. After that, the seeds must first be rinsed thoroughly with water. By the way, rinsing under a tap works even better than, as in our example, with a bottle.
Take the rinsed seeds out of the sieve. They are still surrounded by a germ-resistant, slimy layer. This causes a somewhat delayed or irregular germination in the next year.
Fermentation breaks down germ-inhibiting substances
Place the tomato seeds and the surrounding gelatinous mass in a bowl. Add some lukewarm water and let the mixture sit in a warm place for ten hours. Then stir the mixture of water and tomato paste with a hand mixer for one to two minutes at high speed and let the mixture rest for another ten hours.
Next, pour the seed mixture into a fine-mesh household strainer and rinse it under the tap. If necessary, you can mechanically help with a baking brush. The tomato seeds can be easily separated from the rest of the mass and remain in the sieve. They are now taken out, spread out on a paper kitchen towel and dried thoroughly.
Store tomato seeds properly
As soon as the tomato seeds are completely dry, fill them in a clean, dry jam jar and keep them in a cool, dark place until sowing. Depending on the variety, tomato seeds can be kept for a long time and still show a very good germination rate even after five years.