When anybody wants to dive into seed saving, I always recommend tomatoes be the first crop to start with. Tomatoes are one of the easiest crop varieties to ensure that the seed will come true every year. With the multitude of varieties available, chances are there are at least a few varieties you want to grow every year – even if you’re an experimenter and like to try something new annually. With a cross-pollination rate of about 4% (mainly due to pollinators moving about your garden from one flower to another), which can be lowered to 0% if you use some simple isolation techniques, it’s a great way to get into the world of seed saving.
Tomatoes are actually mostly self-fertile (not self-pollinating, see the glossary for the difference of these terms) and pollinated by movement. Rather then pollinators moving from plant to plant exchanging pollen from other flowers, the majority of tomato pollination occurs through physical movement of the plant, which shakes off pollen from the anthers into the stamen within the same flower. Wind, animals, and large sonicating bees (meaning, bees grab onto the flower and forcefully shake the pollen free with the movement of their wings) are how tomatoes are pollinated the vast majority of the time.
That all might sound like a bit of a biology lesson, but it highlights why tomatoes are a fantastic plant to save seeds from, whether your brand new or a veteran at seed saving.
- Plastic container – 125mL or 500mL
- Cheesecloth or pantyhose (optional)
- Butchers paper, wax paper, tin foil, or a paper plate
- Seed Packets
- Seed storage container
- Desiccate (optional – but recommended)
The first thing you want to do is know what you’re looking for in a tomato. You found a variety that you love, and you want to save seeds. Fantastic! You could just pick any old fruit off the plant and start, but taking a little bit of time and effort will increase your chances of creating a good genetic pool of your own saved seeds.
Pick fruit that is unblemished and disease-free. Picking tomatoes with no cracking and from disease-free plants will increase your chance of passing on any resistances to these issues on to your next years plants.
If you want to encourage a trait, like early ripening for instance, pick the fruit that are first off the plant to save seed from. If you’re growing more then one plant of the same variety, save fruit from as many of the plants as possible to diversify your saved seed gene pool.
Now that you’ve selected your fruit comes the actual saving of the seed. When you open a tomato, all that gel attached to the outer layer of each seed is actually a germination inhibitor – it prevents the seed from sprouting while still inside the fruit. Naturally, this seed coat would break down with rain and weather, allowing the seed to be shed of its gel skin for the next year. Since you’re saving your seed, what you want to do is mimic that natural cycle, but condense it. The way we do this is called fermentation.
- Take your tomato and cut it in half horizontally.
- Scoop out all the gel and seeds into a container.
- Rinse the seeds out a bit to get off the largest of the tomato bits.
- After rinsing, take your container with your seeds, and fill with water. A ratio of 1 part seeds to 3 parts water works well. Any more and the fermentation period takes a lot longer, any less and the water will evaporate before they ferment. Do not place a lid on your container, but if you want to avoid things from getting into it (like flies or pets), use some cheesecloth or an old pantyhose and elastic to cover the top. It’s important to keep air circulating for this process. Place the container in a warm area, away from direct sunlight, where it won’t get disturbed.
- Wait. After the first few days you’ll notice some seeds and slime accumulating on the surface of the water. These are the seed coats and the infertile seeds. Take a spoon and scoop off the infertile seeds and mould, and check the seeds at the bottom. If they are free of the seed coating, move on to step six. If they aren’t done yet, replace the amount of water you scooped out and wait a few more days. Keep checking until the seed coat is gone. This can take anywhere from three to ten days depending on how humid your climate is.
- Once your seeds are free of their coat, give them a final rinse. Prepare an area where they can dry relatively undisturbed for the next week or so. Place them on butchers/waxed paper so they don’t stick to the surface. Tin foil, paper plates, or a fine mesh screen will also work well. Every few days move them around a bit to avoid letting them sticking to the surface.
- When your seeds are dry you will be able to feel it. If you’re in doubt, just let them sit longer. The drier the better, and if you package your seeds wet, they will mould making them unusable the next year.
- Package them up! Plain paper envelopes are best to avoid a build up of moisture, preventing mould or mildew from growing. Make sure to write when they were harvested (month and year), and clearly mark the plant and variety name.
If you are looking to store your seeds long-term, please look at the Create Your Own Seed Bank article.
If you are interested in short term (2 years or less) storage, not as many things have to be taken into account. Tomato seeds stay viable for many years in regular storage (up to five without the aid of cool or cold storage). The purpose of proper storage is to ensure your seeds keep the highest germination rate possible. Take your seeds and your envelopes, make sure to label them with the plant, variety, and the date you harvested them. Gather your seeds and place them in some kind of container – yoghurt, mason jar, an old cookie tin – whatever you can find that will keep them contained.
I suggest also getting a desiccate – the kind that come with new clothing – and placing it in the container with your seeds. This will keep the container dry, once again, keeping mould and mildew from forming on your seeds.
Take your container, store in a cool, dry place, and you’re done.