How to Save Tomato Seeds

I want to know how to save tomato seeds. I seem to recall that I should let the seeds stew in their juices to get rid of disease problems later on and then let them dry out on a coffee holder. Can you explain the process for me?

I have received a surprising number of questions this summer about saving tomato seeds. I hope this is a sign that more people are growing their own tomatoes and perhaps getting interested in some of the heirloom varieties.

Saving tomato seeds is a little bit more complicated than other fruits and flowers because you have to ferment the seeds to reduce seed-borne diseases and remove the gelatinous coating that covers them.

Seed saving works best on heirloom tomato varieties because other varieties such as the hybrids don’t always come back true from seed. If you know the variety name of the tomato you can check its heirloom status online or by looking through seed catalogs. The added benefit of saving heirloom seeds is that you are guaranteed to have a supply of these sometimes hard to find varieties for next year and if you have enough to share, you are doing your part to preserve them for the future.

For the fermenting process you will need:

1 pound size clear plastic deli or storage containers with lids that have been washed and sterilized

round coffee filters

a permanent marker

heirloom tomatoes

small containers with tight lids for storing the seeds (I like to use baby food jars.)

To begin, label the deli containers with the variety name of the tomato seeds you are saving. Next cut the tomatoes in half and squeeze the pulp and seeds into a deli container. Fill the container about half way full; any further and there will not be enough room for the fermentation process. Loosely cover the container with a lid so that air can still circulate and place it in a warm location (about 80 degrees F) out of direct sunlight. When placing the containers you should also consider a location where they won’t be accessible to animals and where you won’t have to smell the fermenting tomato juice.

Depending on the temperature, the seeds should be through fermenting after about 3 to 5 days. Check the progress every day until you see is a film of white fungus on the top of the liquid. If you leave the seeds in the containers too long they will turn dark and begin to germinate.

Once the fermenting process is over you are ready to remove the seeds. Now, I won’t lie to you, this is fairly messy business and it smells pretty bad to boot! Start by removing the white fungus layer and then gently add some water. Swish the liquid around and carefully pour off the liquid. Don’t worry about losing seeds that are floating in the water, these are probably not viable. The good seeds will sink to the bottom. Continue this washing and pouring process until the water runs clear.

Now spread your coffee filters out flat and label them with the seed’s name. Paper plates will work for this as well. The idea is to use something that will wick the moisture away from the seeds, although you should avoid paper towels because seeds tend to stick to them. Dump the seeds onto a coffee filter and spread them out as evenly as space will allow. Place the seeds and filters in a warm location, out of direct sunlight with good air circulation. Stir the seeds daily to break up any clumps and in about 1 week they should be dry enough to store. Store them in a small container with a tight lid such as a film canister or mason jar in a cool, dry location. Your seeds should remain viable for up to 5 years.