As tomato plants do not cross pollinate seeds collected from tomatoes will stay true to type, which makes them an ideal vegetable to save seeds from. Below is a step by step guide on how to collect tomato seeds.
CLEARLY LABEL THE TOMATO PLANTS THAT YOU PLANT AT THE START OF THE SEASON
This is so you do not mislabel your tomatoes when harvesting your seeds. Many tomato varieties produce tomatoes that look similar to other varieties. For example, it is impossible to tell the difference between a Costoluto di Marmande and a Rouge De Marmande tomato as they look identical, yet their harvesting characteristics are quite different.
PICK THREE OR FOUR TOMATOES FROM THE EARLY SEASON CROP
This is because the older plant is the more likely it is to be infected by soil-borne diseases, which can be passed on via the seeds. Do not pick any tomatoes from sickly looking plants (leaves with brown or yellow edges) as they may be diseased.
Note that such diseases are not directly passed on to the seed but are in the gelatinous sac that tomato seeds are encased in. It is possible to separate the seeds from these sacs (see details below) but it is much better to use tomatoes from plants that do not show signs of soil-borne disease.
There are three basic method to save tomato seeds, details of which plus a comparison of their various pros and cons are listed below.
This involves simply smearing the seed encased pulp onto a sheet of paper and hanging it up to dry. Scrape the dry seeds off the paper when you are ready to plant in the new season.
ADVANTAGES SUMMARY
ADVANTAGES
- Involves little time to save the seeds.
- Is a single stage method, the two other methods involve multiple stages.
DISADVANTAGES SUMMARY
DISADVANTAGES
- Awkward way to store seeds.
- Does not separate the seeds from the gelatinous sac they are encased in (increased disease potential).
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Can be difficult to separate each individual seed.
The seeds in tomatoes are encased in a gelatinous sac, it is there to stop the seed germinating in the mainly liquid pulp that surrounds it. The fermentation method is used to remove the gelatinous sacs from the seeds before they are dried.
THE FERMENTATION METHOD STEPS
- SQUEEZE THE SEED LADEN PULP INTO A JAR, STIR IN SOME WATER AND LEAVE FOR ONE TO TWO DAYS AT ROOM TEMPERATURE
Adding water starts a fermentation process that breaks down the gelatinous sacks surrounding the seeds. It is important that you leave the seeds fermenting for no longer than two days as once the gelatinous sacs have completely dissolved the seeds will begin to sprout, making them useless for seed saving. - AFTER 24 TIP THE CONTENTS OF THE JAR INTO A FINE SIEVE AND RINSE WITH WATER UNTIL ALL YOU HAVE LEFT ARE SEEDS
- TIP THE SEEDS ONTO A PIECE OF NEWSPAPER, SPREAD THEM OUT AND LEAVE THEM TO DRY IN A DRY PLACE AWAY FROM DIRECT SUNLIGHT
- ONCE THE SEEDS ARE COMPLETELY DRY SCRAPE THEM OFF THE PAPER, PLACE THEM IN AN ENVELOPE OR AIRTIGHT CONTAINER
Make sure you label the seeds, it is also a good idea to add a use by date.
ADVANTAGES SUMMARY
ADVANTAGES
- Most effective way to remove the gelatinous sacks around the seeds.
- Involves less rinsing than the Water Pressure Method.
DISADVANTAGES SUMMARY
DISADVANTAGES
- If the seeds are left too long to ferment they will begin to sprout
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Is the most complex and time consuming of the three tomato seed saving methods.

Squeezing seed laden tomato pulp into a glass. Stir in a little water and leave to ferment for one to two days.

After a couple of days thoroughly rinse the seeds and tip them onto some paper to dry.
This method involves blasting the gelatinous sacs from the seeds with a high pressure hose, it is not quite as effective at removing the sacs as the Fermentation Method but is much quicker. It is the method I prefer to use.
THE WATER PRESSURE METHOD STEPS
- CUT THE TOMATOES INTO HALVES OR QUARTERS
Depending on the size of the tomatoes. - DISLODGE THE SEEDS FROM THE PIECES OF TOMATO INTO A FINE COLANDER WITH A COMBINATION OF MASSAGING THE PIECES WITH YOUR THUMB AND A LOW FLOW WATER STREAM
- RINSE THE SEEDS WITH A PRESSURE GUN ON A TIGHT SPRAY PATTERN UNTIL THE SEEDS ARE CLEAN
The main aim is to blast the gelatinous sacs from the seeds. The spraying is best done over a garden bed, so you don’t waste the water. - TIP THE SEEDS ONTO A SHEET OF PAPER, SPREAD THEM OUT AND LEAVE THEM IN A DRY SHADED PLACE TO DRY.
ADVANTAGES SUMMARY
ADVANTAGES
- The process takes less time and effort than the Fermentation Method.
- Removes the gelatinous sacs, which means the seeds will not stick together when dried.
DISADVANTAGES SUMMARY
DISADVANTAGES
- Not as effective at removing the gelatinous sac as the Fermentation Method
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Involves more time and effort to process the seeds than the Simple Drying Method.