Tomatoes can be grown quite easily from seed, and you can use seeds collected from tomatoes you’ve grown yourself, or from ones you’ve purchase from the greengrocer!
There are a few tricks to saving tomato seeds, as they are wet seeded crops, which have seeds embedded in the damp flesh of fruits. When tomato seeds are cleaned and dried correctly, they can be stored in a cool, dry place for up to 5 years or longer.
Only two vegetable plant families have wet-seeded fruits, the Solanaceae family, which includes tomatoes, capsicums, eggplants, and the Cucurbitaceae family, which includes cucumbers, melons, squashes.
Which Tomatoes to Use for Seed Saving
Always leave the earliest and biggest tomato fruit, or most productive and strongest plants of the season for seed collection. Resist the temptation to eat the first tomatoes!
To mark which tomatoes were produced first, you can loosely tie a piece of string, wire twist tie or other material that is coloured and stands out. Tie it above the cluster of fruit, or around the stem of the plant.
The great thing about seed saving and growing from your own seeds is that each generation of tomatoes will become, bigger, more productive, and better suited to the local conditions.
The most reliable tomato varieties to use for seed saving are:
- Heirloom varieties, these are open pollinated (non-hybrid) tomato cultivars (cultivated varieties or breeds) that are over 50 years old and have been preserved through generations by careful seed saving.
- Varieties that are known to grow and produce well in your local area.
Which Tomatoes You Should NOT Use for Seed Saving
Never collect seeds produced from F1-hybrid plants. An F1 hybrid is the first generation offspring from a deliberate cross-pollination of two specific parent plant varieties. The seeds will not produce the same plant as the parent plant!
When you buy a packet of seeds, or a punnet of seedlings (small plants), the label will indicate if the tomato variety is an F1 hybrid. Since you can’t save the seeds of F1 hybrid plants, because they are not true-to-seed, skip them and select a more useful variety.
If you buy organic tomatoes from the greengrocer, they will be open-pollinated varieties and not hybrids. So, if you purchase some, and like their flavour, save their seeds and plant them up in spring!
How to Save Tomato Seeds
Tomatoes are wet seeded crops, which have seeds embedded in their damp flesh, so we need to use the process of rinsing to separate the seeds from the pulp when saving tomato seeds.
To rinse tomato seeds:
Step 1. Cut the tomato in half lengthwise.
Step 2. Scoop out the seeds and pulp into a strainer.
Step 3. Put the strainer under moderately pressurised running water.
Step 4. While under running water, rub the contents of the strainer with your fingers, and rinse until the seeds are clean and free of pulp.
Once the seeds have been rinsed free of the pulp, they next step in the seed-saving process is drying.
Step 5. Dry seeds the seeds by placing the strainer in a location with good air circulation, so they can dry as quickly as possible, to reduce the risk of disease, or the seeds getting mouldy.
A convenient location for seed drying is the kitchen windowsill, as shown below. Ideally the position should be warm, but not too warm, and not in hot, direct sun as excess heat can damage the seeds.
Sitting the strainer with seeds on a paper towel for a few minutes first, to soak up the excess water, speeds up drying time considerably.
Other drying methods include spreading a very thin layer of seeds onto a wire screen, a piece of wood, a pan or tray, or any hard, non-stick surface, including the strainer used in the rinsing process.
Keep in mind that seeds will stick badly to paper towels, cardboard, newspaper or cloth if it’s used as a drying surface.
Step 6. Leave the seeds to dry for a few days.
Step 7. Place the dried seeds in a suitable container or envelope, and label it. Include plant name, variety, date collected (and use-by) on the label.
Labelled envelopes of seeds can be placed inside sturdier containers to better protect them. Place envelopes or containers of seed in a cool, dry place to ensure maximum seed storage life.
I can fully agree about the seeds sticking to paper when they are drying. Drying in the drainer or on a plate is much better. Thanks for the informative post Angelo.
You’re welcome! 🙂
I have never had a great deal of luck with tomatoes. However along came a volunteer tomato and wow, we just got crops and crops from just this one tomato plant. I will be saving the seed for sure. I don’t know what variety it is but it’s still producing even now it’s autumn and cold at night here in Western Australia. Only issue was the tomatoes could have been a bit more flavourful. What shall i do next time?
Hi Helen, it’s amazing how vigorous self-seeding tomatoes are! Since the volunteer seedling came up late, it would have had less of the warm weather to ripen its fruit and fully develop their flavour. Sow the seeds indoors in the last month of winter (August in Australia) to start them early, in 6-8 nweeks they’ll be nice strong plants, which can be planted out into the garden as soon as the last spring frosts have passed.
I have had great success with a quicker and simpler method. Just label a piece of kitchen paper with the variety and date, then smear the fresh seeds/pulp over it, separating the seeds from each other as much as possible with your fingers. Let the paper dry in the kitchen for a few days then when dry, store in a labelled paper envelope until spring. This method quickly makes a stored form of the unprocessed tomato seed which is much the same as the “seed tapes” which are now sold commercially. It is widely thought that leaving the pulp on the seed prevents germination but I have never found this to be so.
Some more tips:
A further advantage of having the seeds stuck to paper: because the seeds are small and home gardeners don’t need a large number of plants of each variety, then to plant the seeds in punnets (or the ground), use scissors to cut off individual seeds with their attached paper, which acts as a handle and allows you to see them better. Place the seeds/paper on the seed raising mix and cover with a thin layer of the same mix. Mild bottom heat will promote germination. After germination, water as needed with a weak Maxicrop/seaweed solution until ready for transplanting into the garden.
A cheap source of seed raising mix is sieved regular potting mix (sieved through a 3 to 4 mm plastic garden sieve to remove the larger lumps, which themselves can be used on the bottom of the punnet to stop potting mix from falling out through the holes in the punnet).
Plant the seedlings into holes and hill up the soil as the plants grow so that the bottom part of the stem is underground once the hole is filled.The underground stem sends out side roots which makes the plant stronger and less likely to fall over prior to staking. Mini greenhouses can be made from clear plastic bottles with the bottom cut off but leave the lid off the bottle so that excess heat and humidity don’t build up around the seedling.
Thanks Stuart, these are great tips!
Leaving the pulp can cause the seeds to go mouldy, and delay germination. You can clean the seeds in a sieve under running water, then place them on a paper towel to dry, and they will still stick far to well to the paper, I’ve tried it. In that case, tear the paper into smaller pieces and sow with seed side up, paper side underneath.
I also sift potting mix to use as a seed raising or seed covering mix, works great. You can use a small 15cm (6″) plastic pot which has lots of drainage holes underneath, as opposed to a few large ones on the bottom edges, works great as a cheap potting mix sieve!
It’s definitely better to plant tomato plants deeper (remove lower leaves if necessary), they establish much faster and grow new roots along the stem. This should only be done with tomatoes, other plants will usually get stem rot!
The plastic bottle greenhouses are also a great way to stop snails, slugs and other pests from eating newly planted seedlings, but in this case leave the top off, it’s not needed, and the plants wont get cooked in sunny weather.