There’s a unique kind of joy in growing tomatoes in your backyard, but you know what’s even more rewarding?
Harvesting your own tomato seeds! This lets you enjoy your favourite flavours season after season.
Just keep in mind that not all tomatoes are suitable for collecting seeds. You’ll want to start with heirloom or open-pollinated varieties — and luckily, these are usually the most delicious ones.
Then, proper storage matters to keep the seeds viable for many years.
Curious about how to save tomato seeds? This blog explains everything you need to know: from picking the right fruits to get seeds from, to storage, to preparing for sowing!
When to Pick Tomatoes for Saving Seeds | Harvesting Tomato Seeds | Storing Tomato Seeds | How to Prepare for Planting
Can You Save Seeds From Any Tomato Variety?
No, not all tomato varieties are ideal for saving seeds.
While you can harvest seeds from any tomato, they may not grow into the same plant or bear the same fruit as the parent.
What’s the best tomato for saving seeds?
The best tomatoes for saving seeds are heirloom varieties.
Heirloom tomatoes are open-pollinated plants, meaning they naturally reproduce with help from wind or insects.
Their traits also stay stable from one generation to the next. So when you grow their seeds, the plants and fruits you’ll get are identical to the source.
Even better, heirlooms are cherished for their excellent flavour. That’s why gardeners and culinary enthusiasts have been preserving their seeds for decades!
Can you save seeds from hybrid tomatoes?
This is not ideal if you’re after the best flavour.
Hybrid tomatoes are F1 (first generation) plants produced by intentionally crossing two different tomato varieties.
Their seeds will grow into the F2 (second generation) plants. However, they’ll likely show a mix of unpredictable traits.
F2 tomatoes often lose the original features of the parent plants. They might be weaker or produce a smaller yield, and the fruits may not have the same taste or quality.
When Should You Pick Tomatoes for Saving Seeds?
While you can pick tomatoes right after the breaker stage, it pays to wait a little longer if you’re after good seeds!
The best time to harvest tomatoes for seed saving is when they’re fully ripe on the vine. Some even let them go slightly overripe.
This gives the seeds more time to develop, which boosts their chances of germinating later.
Wait until the tomatoes reach a deep, mature colour. That could be red, yellow, orange, or whatever is typical for the variety.
They should also feel a little soft — just like how you’d want to eat them.
How to Harvest Tomato Seeds for the Next Season
Want to save your own tomato seeds for the next gardening season? Good news — the process is simple!
Just be sure to do it right to set yourself up for strong, productive plants.
Step 1: Identify the best tomato plants
To get vigorous, disease-free plants for the next season, you need to pick the best tomato vines to get seeds from.
These should be your healthiest and most productive heirloom tomato plants. Make sure they’re not showing any signs of infection.
Step 2: Choose the right tomato fruits
Next, you have to pick the perfect tomato fruits for collecting seeds.
Use fully ripe fruits from the first harvest of the season. Their seeds are more likely to grow into plants that fruit early and grow vigorously.
Try to avoid the tomatoes from the last batches. At that stage, the plants have already been exposed to more weather stress or disease, so the fruits often don’t have the best quality.
Then, make sure the tomatoes are in great shape.
Skip those with cracks, splits, or holes. Damaged fruits can carry disease, and you don’t want to pass that onto next year’s plants.
Step 3: Extract the tomato seeds
Now that you have your tomatoes, it’s time to extract the seeds!
Grab a clean knife and cut the tomato fruits in half, crosswise. Avoid slicing from top to bottom, as that will make the seeds harder to remove.
Next, use a spoon to scoop the seeds or just gently squeeze the tomato until the seeds pop out. You have to include the gel around the seeds, as that’s needed for fermentation later.
Place the seeds and pulp into a small, clear jar. Glass jars are best because they’re easy to clean and sterilise, but plastic works too.
Do not fill the container to the brim — it should be only about two-thirds full or less. Have more jars ready if you’re saving plenty of seeds.
When collecting seeds from different tomato varieties, label each jar. Write the tomato variety and the date so you can easily tell your seeds apart!
Step 4: Prepare the seeds for fermentation
It’s highly recommended to ferment tomato seeds to boost germination and create healthier plants!
Each tomato seed is wrapped in a jelly-like seed coat, which contains germination inhibitors. In other words, it prevents seeds from sprouting inside the fruit.
When a ripe tomato falls to the ground and breaks open, microbes start breaking down that coat, allowing the seeds to germinate.
Fermentation mimics this natural process.
It encourages good bacteria and yeast to grow on the seeds, which helps dissolve the gel sac. Plus, it can also help get rid of any tomato diseases and infections on the seed.
To start fermenting the tomato seeds, add water to the jar. Pour in about half the amount of the pulp, then gently stir the mixture. The added liquid helps create the ideal conditions for beneficial bacteria to develop.
Cover the container loosely with a paper towel or any breathable cloth, then secure it with a rubber band. Do not seal it tightly to allow airflow.
Step 5: Let the tomato seeds ferment
Keep your tomato seeds in a warm place out of direct sunlight. Once or twice a day, gently stir the mixture.
Over the next 2–4 days, the tomato pulp will ferment. You’ll notice a sour, yeasty smell (like sourdough or beer), and a layer of white or grey scum on the top.
That’s completely normal and a sign that the fermentation process is working.
As the gel coating breaks down, the good seeds (those capable of germinating) will sink, since they become heavier with a healthy embryo.
The bad ones (those that won’t germinate) usually stay afloat.
You can stop fermenting once most of the tomato seeds have settled at the bottom of the jar.
Just keep in mind that warmer temperatures can speed up the process. Sometimes, tomato seeds can ferment overnight or within 24 hours, so check the mixture regularly.
Step 6: Clean the tomato seeds
After fermentation, you’ll need to discard the bad tomato seeds and clean the viable ones.
Use a spoon or a small strainer to scoop the mouldy pulp and any floating seeds. Dispose of these in a sealed bag.
The viable seeds are those left at the bottom of the jar. They may still be covered in scum, so you’ll need to rinse them thoroughly.
Add fresh water to the jar, stir gently, and wait for the seeds to sink again. Slowly pour out the cloudy water while keeping the seeds in the jar.
Repeat rinsing and draining until the tomato seeds are clean. You might have to do this about 3–5 times.
For the final wash, pour everything onto a colander with a fine mesh to drain the excess water.
Then, hold the colander under running water for about a minute. You want to make sure you’re left with only clean seeds for drying.
Step 7: Dry the tomato seeds
Once your tomato seeds are clean, transfer them to a flat, non-stick surface, like a ceramic tray or glass plate.
Do not use paper towels or paper plates. The seeds can stick to them permanently!
Spread the tomato seeds out in one layer, then keep them in a dry, cool place. Allow them to air-dry for about 1–3 weeks.
The seeds must be completely dry before you store them. You’ll know they’re ready when they feel hard and brittle — bending them should make them snap.
How to Store Tomato Seeds
Fermented, fully dried tomato seeds can remain viable for many years, as long as they’re stored correctly!
Preparing tomato seeds for storage
Place the dried tomato seeds in small paper envelopes, and label them with the variety and the date.
Next, tuck the envelopes into an airtight container, such as a glass or plastic tub, to keep moisture out. You can add a few packets of silica gel to help reduce humidity.
As for storage, you have three options:
- At room temperature
- In the refrigerator
- In the freezer
Option 1: Storing at room temperature
If you’re saving tomato seeds for the next season, you can just store them at room temperature.
This method is the most convenient, since you don’t have to thaw the seeds once you’re ready for planting.
Just keep the container in a cool, dark, and dry spot, such as a pantry or cupboard.
Remember that tomato seeds stored this way remain viable for only about 2–3 years, so you’ll have to use them before they go bad.
They can also be more susceptible to pests or moisture if the container isn’t properly sealed.
Option 2: Storing seeds in the fridge
To extend the lifespan of tomato seeds, pop the container in the fridge at around 4°C–10°C.
Refrigerated seeds remain viable for up to 5 years, as cooler temperatures can slow down the ageing process. Plus, they can reduce the risk of mould or pests.
Just make sure that the seeds are in an airtight container, ideally with a silica gel packet.
Option 3: Storing seeds in the freezer
Freezing your tomato seeds is the best method for long-term preservation. This can keep them viable for 5–10 years, maybe even longer!
However, if you plan to keep the seeds in the freezer, proper preparation is important.
Before freezing the seeds, make sure they’re completely dry. Place them in paper envelopes, then keep them in an airtight container with a packet of silica gel.
Keep the container in a cool, dry place for another 1–2 weeks to let the tomato seeds dry even further. This is essential to absorb any remaining moisture.
Afterwards, slip the airtight container into a heavy-duty freezer bag for an extra layer of protection against moisture.
Store the tomato seeds in the freezer, ideally near the back, where temperatures are most stable.
Preparing Tomato Seeds for Planting
Now that you’ve dried and stored your own tomato seeds, how do you get them ready for the garden?
The steps are pretty straightforward but differ a bit depending on how the seeds were stored.
Start by preparing the seeds for sowing and checking if they’re still viable.
How to get the tomato seeds ready for sowing
As the next growing season approaches, you need to prepare your tomato seeds for planting.
Frozen seeds need to be thawed slowly. First, transfer the container to the fridge and leave it there for 2 days. Do not open the container at this point!
Then, move the seeds to room temperature. Choose a cool, dim, and dry space, and wait for another 24 hours as the seeds acclimate. After that, it’s safe to open the container.
For seeds stored in the fridge, take them out and keep them at room temperature away from direct sunlight. Only open the container after at least 24 hours.
If your seeds have been stored in a cupboard, there’s no extra preparation needed. You can go straight to checking their viability.
How to check if the tomato seeds are still viable
Sometimes, it’s easy to tell if tomato seeds have gone bad while in storage. Check for:
- Mould or fuzzy growth
- Musty or unpleasant smell
- Seeds that have turned brown or black
If you notice any of these, it’s best to throw out the affected seeds.
You can also do a germination test. Place 10 tomato seeds in a damp paper towel inside a sealed bag, and wait 5–7 days.
If fewer than half sprout, the seeds have low viability. You can still plant them, but it’s better to sow multiple seeds (about 3–4) per planting hole and thin them out later.
If most of them sprout, your batch is healthy and strong. These tomato seeds are ready for sowing!
Be sure to plant the tomato seeds at the right time. They need consistent warmth and moisture to sprout, so getting the timing perfect is crucial.
How to keep tomato plants healthy
Once the seedlings appear, make sure to provide the right growing conditions for the tomatoes. They need a warm climate and 6–8 hours of full sun daily.
In the next weeks, regular care will keep your vines thriving, so consistently water, fertilise, and prune your tomatoes.
You’ll also need to build sturdy supports for the tomatoes. Most heirloom varieties are indeterminate (vining types), so they need extra help to stay upright.
Need help planting your seedlings or maintaining your garden? You can book a professional gardening service to get everything set up and keep your plants strong!
FAQs About Harvesting Tomato Seeds
Got more questions about the seed saving process?
We’ve got all the answers, whether you’re working with different tomato varieties or want to skip the fermentation step!
Can I save seeds from supermarket tomatoes?
You can, but the results are unpredictable.
Many supermarket tomatoes are hybrids, so you might not get plants and fruits that are identical to the parent.
Heirloom, homegrown tomatoes are more reliable for saving seeds!
How to save seeds from cherry tomatoes
You can save seeds from cherry tomatoes using the same steps you’d use for other varieties.
The same process also works for beefsteak, slicing, or paste tomatoes.
Just make sure you’re collecting seeds from an heirloom or open-pollinated variety to make sure that the next generation grows true to type.
Can you save tomato seeds without fermenting?
Yes — the process will be quicker, but there are cons. Skipping fermentation can lead to:
- Shorter viability
- Higher risk of disease
- Lower germination rate
If you want to save tomato seeds without fermenting, extract them from the fruit and place them in a strainer with a fine mesh.
Wash the seeds under running water while gently scrubbing them with your hands. This helps separate the seeds from the pulp.
Once they’re clean, spread them out on a glass or ceramic plate and let them dry completely for 1–3 weeks.
Afterwards, tuck the seeds inside a paper envelope. Keep everything in an airtight container, and leave it in a cool, dark spot or your fridge.
Can I dry tomato seeds with an oven or dehydrator?
No, too much heat can kill the seed embryo, which means it won’t germinate later!
Tomato seeds are best air-dried at room temperature, out of direct sunlight.
Can tomato plants cross-pollinate?
Yes, but it rarely happens.
Tomatoes are self-pollinating, so each flower can fertilise itself. However, cross-pollination can sometimes take place if you have multiple varieties growing too close to each other.
To make sure your seeds stay true to the parent, allow some space (3–4m) between different tomato varieties.
