Saving Tomato Seeds

Tomato seeds are one of the easiest types to save. Tomato plants are mostly inbreeding, meaning it’s unlikely tomato plants will cross pollinate with each other and plants grown from the saved seeds will produce more tomatoes of the same type.

Seeds can only be saved from open pollinated or heirloom types. Seeds saved from hybrid types will likely be genetically unstable and lead to unpredictable results.

Ideally, tomato plants will be grown a half meter apart in rows 1 meter apart. Preferably you will grow about 5 of the same type in a row, and save seeds from the middle 2 or 3 plants. In this way, you will have some genetic diversity by using more than one plant, and you will minimise the already small risk of cross pollination by isolating the varieties from each other with a little space. In doing this, your rate of crossing should be far below 5%. If you can’t do this, or you only have 1 or 2 plants of each variety, don’t worry, you will probably achieve good results no matter what.

There are contradictory reports of wild or currant tomatoes crossing with each other and with other tomatoes. To minimise the risk of crossing, don’t grow these types of tomatoes near any other plants except those of the identical type when saving seeds.

Only save seeds from the most tasty and good looking tomatoes to ensure you do not select any that are genetically predisposed to be of poorer quality. If possible, select seeds from the first few tomatoes that ripen on each plant, as these are likely to have the healthiest seeds.

Okay, on to the seed saving part. Fermenting seeds helps prevent some diseases, and also removes the gelatinous coat on the seeds. If you don’t wish to ferment them, just skip the steps below and spread them out on a coffee filter to dry.

To ferment the seeds, first slice your tomato or tomatoes along their equator, and scoop the seeds into a non metallic fermenting container. If desired, you can add a few tablespoons of water, but it’s not necessary. Cover the container with plastic wrap, and poke a few holes in it. Put in a warm place (about 70F or 22C), protected from direct sunlight, and leave undisturbed for 3-5 days. Fermenting is an anaerobic process, meaning exposure to oxygen will disturb it, so the contents of the container should not be stirred. There will be a layer of slimy mold growing on top and, after fermenting, you should scoop as much of this off as possible.

Now rinse the seeds off by holding the fermenting container under slowly running water. Mostly the seeds will sink to the bottom, and everything else will float. By gently helping the debris over the edge of the container with the running water, you will be left with only seeds. If any seeds do float, they are bad, and you can let them wash away.

Now pour off as much water as possible, and put the seeds on a piece of coffee filter paper to dry. Do not use any other type of paper like a paper towel, or the seeds will stick. At this point you have about a week to completely dry the seeds before they start germinating. Place them in an airy place, protected from direct sunlight.

When they are dry, put the seeds in a paper or plastic envelope and store at a steady temperature in a dry place. Only store them in plastic if they are completely dry.   Some place dark without frequent temperature changes like the back of a closet or cabinet is a good choce of storage location.  Properly stored seeds will last about 10 years.