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Saving & Storing Tomato Seeds

How to Save Your Tomato Seeds

Be aware that you will only be able to save seeds from non-hybrid, open-pollinated, heirloom tomato varieties.

If you are selecting tomatoes that you have grown yourself, choose only ripe tomatoes for seed-saving. I suggest selecting the first fruits to ripen versus waiting later in the season to reduce the chance that your selected tomatoes will have cross-pollination occur from bees or other insects.

To be assured that you are saving seeds from tomatoes that are true to type, be diligent to inspect your fruit that it does indeed appear to be true to the variety description.

I have always chosen to use the natural fermentation process that follows. This process helps remove undesirable, harmful pathogens that may cling to the seed. This also makes for having cleaner seed to store and pack.

If you are going to be saving tomato seeds for multiple varieties of tomatoes make sure that you keep all of your different tomato varieties and the seed saving materials for each separate to avoid mixing up the varieties. There are many opportunities in this process to mix up the strains by having seeds misnamed or misplaced.

Materials needed:

  • Knife for cutting tomatoes
  • Plastic deli containers or small drinking cups
  • Permanent marking pen
  • Paper towels or napkin
  • Teaspoon
  • Fine-meshed kitchen sieve
  • Paper plates (uncoated)
  • Containers for dried seeds (glass with sealable tops, small plastic zip-lock bags or manila coin envelopes.)


  1. Mark the plastic container with the name of the tomato variety along with the date.
  2. Cut the tomato in half and squeeze the seeds and gel each half into the cup. You may cut away the remaining core and pulp for composting or using in a sauce or other food.
  3. Add some water if there is not sufficient liquid to swirl.
  4. Move to the next tomato variety making sure you have cleaned all the seeds from surface and tools used in your previous selection.
  5. Cover the cups with a paper towel to keep insects out of container.
  6. Move the cups outside in a shady area or inside in a location that will be undisturbed. Fermentation will be completed in 2-5 days depending on the ambient temperature. (Over 80 degrees perhaps 2 days. Cooler conditions may take longer.) You will know when fermentation has been completed because a foamy, smelly, fungus will appear on the surface.
  7. Then add water to within an inch of the top of the cup to rinse the seeds using a spoon to break apart the solids and pour off the solids. If you are not using the benefit of a slow running faucet you will add water and rinse off the scum and the floating bad seeds several times until the water is clear with your good seeds remaining on the bottom of cup.
  8. Pour off the clear water with the good seeds into the sieve.
  9. Press the seeds with a spoon to squeeze out remaining water from inside the sieve and blot the outside bottom of sieve with a paper towel to remove any remaining drips before pouring the seeds onto a paper plate that has been marked with the tomato variety name.
  10. Spread the seeds into a single layer on the plate so they will dry easier. Depending on the temperature the seeds should be dry within several days and then can be added to the storage container.

Seed Storage

When storing tomato seeds it is most important to keep your seeds away from exposure to moisture. If you are storing seeds in a moist, hot or tropical climate in their paper packs your seeds will have a shorter viability. Generally, commercial seeds should last around five years if stored in cool, dark, dry location. Most seed companies do germination testing annually so you can be reasonably assured of a few years of viability. Within our special 'seed bank' storage (where we save tomato varieties that we no longer currently grow or tomato seeds that we've been sent that we haven't yet included in our annual seed trials), in a cooled, de-humidified, dark area, we have been successful germinating seeds up to fifteen years with almost 100% germination.

You can best store your seeds safely in any of several ways:

  • Put your seed packs in a sealed zip-lock bag, glass jar, plastic vial with a tight snap-lid, or even in coin envelopes if they are kept in a de-humidified room. I prefer storing my seeds in a cool, dry, dark location. Some people have the space and ability to store their seeds in their fridge or even a freezer. Although going to this extent is not necessary, if you do so it would be best to store your seeds in a plastic vial with a pack of silica gel. But allow seed to thaw before opening the container so the moisture of the outside air does not fill the container when opened.
  • Be sure to label your container with variety name and date first saved.