It's supposed to make them more disease resistant. I've saved tomato seeds by just drying them and by fermenting them and didn't notice any difference.

Fermenting not only dissolves the oily seed coat so the seeds dry more effectively but properly done, the beneficial fungi that develops kills many bacteria that can be transmitted by seed. Further disinfecting can prevent the spread of even more seed-borne disease.

Dave

How do you ferment them ?

Here is an easy way to ferment them. I generally start fermenting as soon as I start getting lots of ripe tomatoes, and do it periodically during the Summer, so I can avoid the "end of season rush" when it could be too cold.

Harvest seeds from your tomatoes by cutting the tomatoes open and squeezing the seeds and gel into a plastic cup. Collect enough to fill the cup up to 1/3 full of seeds and gel. It can be less full, too, in which case use less water in the steps below.

Mark the plastic cup with the name or variety of the seeds that are in it. Generally you will want to get seeds from several tomatoes on the same plants or from 2 or 3 plants of the same variety.

Add tap water to the cup. I generally put 2 to 4 times as much water in the cup as I have seeds and gel.

Set the cups in a moderately warm (but not hot) place. A workroom, a garage or outside. Most of the time you want the temperature between about 65 and 85 degrees. It is true that the cups may attract fruit flies and have some odor to them, but I don't generally notice the odor, so I have even done them inside in my laundry room or similar places. If you put them outside, keep them away from the wind, or places where they might spill. It is probably okay if they have a little sunlight on them, but not where they will get hours of bright sun every day. That might heat the water too much and sterilize your seeds.

Let the cups sit from 3 to 7 days, depending on temperature. The cups may develop fungus inside the water and/or a scum on top. That is okay. You don't need to do anything with the cups while they are sitting and fermenting.

After 3 to 7 days, stir the cups slightly, then give them 20 or 30 seconds for the seeds to settle towards the bottom. Pour off most of the liquid that is in the cup, taking care to try to avoid pouring off the seeds in the bottom.

Run more (lukewarm or room temperature) tap water into the cup. Let the seeds settle again and pour off the liquid on top again.

Repeat the adding water and pouring off process until the water runs clear and the seeds are clean. Then pour off ALL of the water if you can, again, making attempts to preserve the seeds in the bottom.

Get a PAPER PLATE to put the seeds on (NOT plastic). Or maybe some very thick, strong paper towels. You want the paper plate to 'wick' the water away and let the tomato seeds dry within a few hours to a day or so, or the seeds may start to germinate.

On the paper plate, mark the name of the tomato variety and the YEAR of the harvest.

Pour the seeds remaining in the cup (after pouring off the liquid) onto the paper plate. Spread them around with your finger to avoid deep clumps (so they dry better). Set the seeds where they can air dry. You don't generally want to stack these plates on top of each other or they won't dry fast enough.

Let the seeds dry for a week or two. Then take them and separate them off the plates, by rubbing them off, and putting them into little coin envelopes (with the variety name and year of harvest marked on the envelope), or if you are really lazy, put the paper plate with the seeds on it into a large plastic bag and seal it.

Store them at room temperature, out of the heat and sun and cold, and away from all moisture. My seeds easily maintain good germination ability for 10 or 12 years when stored like this.

This method seems complex, because I have described it in detail, but it is actually quite easy and produces professional quality seeds.

"This method seems complex..., but it is actually quite easy and produces professional quality seeds." I totally agree. Once I got my head around the procedure, I collected seed last year - 100% germination rate. (I store mine in the fridge crisper along with my other seeds.)

Here is a picture I posted on facebook, showing the seeds in a cup, just after I collected them and added water to ferment.

Here is a link that might be useful: Fermenting Tomato Seeds

fcvivish, for some reason I can't access your facebook page.

I used this website as a guide.

Here is a link that might be useful: Fermenting seeds

Don't know why the facebook page isn't showing up for you. It shows up for me, but then it is MY page, so maybe the settings for other people are wrong. If this continues, please let me know.

The website that you list does an excellent job of describing and showing the process. There are always slight variations from one person to the next in how they do it, but that just goes to show you that it works, and isn't really too hard to do.

Fermenting doesn't NEED to be done, but it is nice because it produces clean, healthy seeds if done right. I have also smeared tomato seeds on napkins (especially when visiting other countries) and dried them and mailed them to myself. This works fine. I understand in Italy they used to just smear the seeds on old rags. But fermentation produces nice seeds like we are used to seeing when we buy them.

Garden Web FAQS: How to Save Tomato Seeds

Well THIS is an interesting find:
Fermenting the tomatoes themselves......

Here is a link that might be useful: Tomato Wine

Dave
You said that in addition to fermenting, "Further disinfecting can prevent the spread of even more seed-borne disease". Can you please describe the technique for further disinfecting seeds?
thanks
Mike

There are several ways to disinfect seeds. My personal preference is simply to mist them with a 1:10 bleach solution. Then dry them well. Some prefer to use diluted hydrogen peroxide. I use cheap disposable coffee pot filters for seed drying.

Other methods of disinfecting are discussed in the Saving Tomato Seeds FAQ and in other discussions here.

Dave

Thanks everybody about fermenting and disinfecting and saving tomato seeds.

I also kind'a like the idea of letting the tomato rot( = ferment). That is the way how in the nature it happens.