Fermenting tomato seeds.

I was checking on some heirloom seeds the other night, and it said to ferment the seeds before I plant them. Can someone tell me the ends and outs on this. I'd hate to loose the seeds that my dad gave me. thanks, Mike

Hi Mike!

There's a ton of info on fermenting tomato seeds around here, and it's a lot to wade through. This is from a post by Carolyn, and can be found somewhere in the Tomato forum. I have it copied to my hard drive so I can find it. --Rhonda
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Subj: Seed Saving
Date: 01/27/2002 1:07:54 PM Eastern Standard Time
From: Cmale
To: Cmale

Below is a post I wrote about four years ago. And I'm glad I found it because
I just wasn't up to doing it from scratch.LOL

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Seed can be saved from any tomato you're growing, but if it's an F1 hybrid the seed will not come true when planted the next year. So most folks save seed only from open-pollinated strains, where, if no cross-pollination or spontaneous mutations have taken place, the saved and sown seed does come true when planted the next year.

You can just take the seed, try to wash it well and dry it on a plate or towel, but that's not the best way to do it. All seed has the potential to carry along with it certain pathogens, or bacteria and fungi and viruses which can cause disease. All seed companies ferment their seed to lower the amount of pathogens,and fermentation is easily done at home. All seed companies also treat the fermented seed with a triphospahte solution to get rid of tobacco mosic virus (TMV), but the solution is very caustic and TMV is NOT a common tomato pathogen outside of a greenhouse setting. Your fermented seeds will be squeaky clean and fuzzy, just like purchased ones.

There is a right way and a wrong way to select fruit for seed saving. Doing it the right way you'd have at least 6 plants of one variety and you'd select firm, ripe fruit, if they're growing in a row, from the inner four plants, to lessen the chances of insect cross pollination of your selected fruit. You'd
take fruit from all four plants and process it. Since every single plant is slightly different from the other plants of it's variety , this is the way to maintain what is called genetic diversity within the variety. But most folks don't have 6 plants. So. I'll tell you how to save seed the wrong way. LOL Select the best specimens you can, and never process just one or two fruit because you can't tell by just looking at the fruit whether or not an individual fruit has been cross-pollinated. If I'm processing White Queen I might have 10 white tomatoes in front of me. I'd like to think that all 10 were self-pollinated and the seed is pure. But I don't know that.

Fruit that are cross-pollinated are identical to non-cross-pollinated fruit, so I must be sure to process enough fruit to maintain the variety.If you have only one plant of a variety, so be it. And also remember that if you are saving seed from varieties staked or caged next to each other your chances of cross-pollinated fruit are higher because of the closer physical proximity.

There are many variations as to how to do the fermentation. I'll tell you how I do it, and then mention a few of those variations. I get one lb clear deli containers at the store. Put tape on the container and label with the variety name. Squeeze enough pulp and seeds into the container so it's at least half full. If it's a Roma or paste type you usually don't have much juice and you'll have to add a tad of water. Place the containers out of the sun and where critters won't tip over the containers and where the smell and accumulated fruit flies won't drive you crazy. After 3-5 days you'll see a white mat of fungus develop over the top of the contents and if you look at the bottom of the gook you'll see little bubbles indicating the fermentation process is occurring. DO NOT STIR the mixture. Yes, I know, some folks say to stir it. They seem to forget that fermentation is a process which takes
place in the absence of air (is anaerobic) and stirring introduces air.

Now what's happening in that container is that the acidic conditions are killing the viruses and the fungi and the mold is making antibiotics which kill the bacteria. Also, the gel capsules around the seeds are being destroyed and that's good because they have a germination inhibitor in them.
So, it takes about 5 days for me before I can process the seed, longer or shorter depending primarily on the temperature. By trial and error you'll learn when the seed is ready to be processed. If you do it too soon the gel capsules are still sticky around the seeds and if you do it too late the seeds turn brown, although they still are viable.

So now you have your containers of stinking goop with fruit flies circling low. I sit down on the front porch steps. Between my legs I have a big bucket and in my left hand (I'm right-handed) I have a hose with a pistol type nozzle. I spritz some water into the container and swirl the contents. The
good seeds will fall to the bottom and the immature seeds will float. I carefully pour off some of the goop. Usually the fungal mat goes in the first pour off. Yes, you'll lose some seeds that have stuck to it;not to worry. I continue this spritzing with water, swirling and pouring off until the water is perfectly clear and the seeds are at the bottom. Now I've prelabeled paper plates with the variety name. Don't use coated plates, just real paper because the coated ones won't absorb the water. Carefully drain off as much water as you can and dump out the seeds on the plate, Spread the seeds around
with your finger so you have a single layer. If you don't do this you can get germination of the wet seeds on the plate. DO NOT DO THIS STEP OF DUMPING OUT THE SEEDS IF THE WIND IS BLOWING OR OFF GO THE PLATES INTO THE WILD BLUE YONDER.Place the plates inside, where the seeds can dry. I festoon all the upstairs bedrooms at mom's place with the paper plates. When the seeds are thoroughly dry (takes about one week for me but depends on temps and
humidity) I put them into little capped plastic vials that I "borrow" from work.

LOL Any small airtight container is fine. Some good ones are sold at Southern Exposure Seed Exchange. Now if I were going to be doing this the absolute right way I would add silica gel to the seeds and dry them down to a moisture content of about 8%. I don't do that. And if I were going to be doing this the right way I'd store the seeds in the freezer or the fridge, but I can't because I have over 600 bottles of labelled seed. So they stay in my apartment where the temps in the summer can get up over 90 and the seed viability on most of my 5 year old seed is in excess of 80% and that's just fine with me.

Now you can scale down the containers to use large Dixie Cups. And you can pour the gook into a sieve and try to separate the seeds that way. That has NEVER worked well for me. The basic thing is to get the fermentation of those seeds done.

I've probably forgotten a bit here and there, but I think the main gist of the process I've described well enough. Sure it's a stinky messy procedure, but when you're done and see those beautiful fuzzy clean seeds it really gives you a sense of accomplisment.

Ah, yes, i forgot to say please cut your fingernails before you do this. Seeds can get caught under your nails and then you can transfer seed from batch to batch. And I mean here, primarily when you are squeezing the pulp and seeds into the containers, but also when you're going from variety to
variety with the fermentation containers. AND RINSE YOUR HANDS WELL AND CHECK UNDER YOUR FINGERNAILS FOR SEEDS as you go from variety to variety.

Carolyn

And I'd like to add to that seedsaving post I just posted.

First, most of you aren't going to be saving seeds in the amounts that I would, so if you don't want to use the one pound clear deli containers, use something smaller, but still a CLEAR container. Clear
containers are useful for monitoring the fermentation process becasue you can see the bubbles along the sides of the clear container and you can see how well the gel capsule material is being destroyed.

Seeds last a long time so there's really no reason why you shouldn't do the fermentation in a one pound clear deli container (takes maybe 2-3 big beefsteaks or many more smaller ones and tons of cherry types,LOL. But why not use those clear 8 oz beverage glasses if you wish. Using something shallow is not good because of evaporation.

And keep an eye on the fermentation becasue sometimes the liquid evaporates before the fungal mat is formed and you have to add some water to reconstitute it if it dries down too much.

As I said in my post, I seldom add water to the fermentation mix; the juice of the tomatoes alone is just fine. If juice is scanty then add just a bit of water.

Oh, and if you're doing lots and lots of fermetations you can make the process go faster by saving the first poured off liquid from a fermentation and add it to newly squeezed containers where it will
then speed up the fermentation. But be very sure there are NO SEEDS in thatliquid. Kind of like using starter for sourdough bread or same for yogurt.

Fermentation does NOT remove all pathogens from the seed. It lowers the amount found on the surface but obviously cannot remove any pathogens in the endosperm (inside) of the seed. But the most commonly transferred pathogen is Fusarium and it does a great job at lowering the levels of that pathogen.

If you have any questions,please just ask.
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edited for formatting "wonkiness"

This message was edited Sep 19, 2004 10:41 AM

Carolyn's advice is excellent. For those of us who are more visual-oriented Dave did a how-to with pictures in his journal: http://davesgarden.com/journal/j/viewentry/7740/

But he didn't finish it, Terry!