I have some tomatoes in the freezer from last year and I'd love to save the seeds from certain varieties. Would it be possible to ferment them as normal after they have been deep frozen and then thawed?

Linda

I believe the answer is no. Because of the moisture in the tomatoes and their seeds, the freezer temperature bursts the cell walls, and the seeds are not viable.
The difference between this and freezing seed after they've been fermented and dried, is the moisture content.

Iirc we had a discussion about this question some time ago, and [mention]Nan6b[/mention] was doing the experiment to test if it could be done or no. I don't recall if she reported her results, but perhaps she'll see this and reply.

I've tested it and it did not work, unfortunately.

Thanks Bower and PhilaGardener. I thought that I could boost my seed supply from these frozen ones that are a year old and about to go in the composter to make room for the new ones, but I will stick to harvesting fresh seeds.

Linda

I understand and agree about frozen seeds not being viable. What I need an explanation of is how I have so many tomato volunteers popping up in the spring after a long, freezing winter. I would think my frozen ground would pop the seeds, too.

Paulf wrote: ↑Mon Jul 26, 2021 12:24 pm I understand and agree about frozen seeds not being viable. What I need an explanation of is how I have so many tomato volunteers popping up in the spring after a long, freezing winter. I would think my frozen ground would pop the seeds, too.

That is a question that I have always pondered. The volunteers germinate beautifully and are nice hardy plants. Perhaps it is because many of the seeds that are from fruits that have rotted on the ground were fermented in that rotting fruit and so did not have a gel coat on them to pass the freezing winter.

It's because they dry out enough before the freeze.

Labradors wrote: ↑Mon Jul 26, 2021 10:25 am Thanks Bower and PhilaGardener. I thought that I could boost my seed supply from these frozen ones that are a year old and about to go in the composter to make room for the new ones, but I will stick to harvesting fresh seeds.

Linda

Just how much of a boost do you need, asks Captain Enabler?

worth1 wrote: ↑Mon Jul 26, 2021 1:48 pm It's because they dry out enough before the freeze.

Yes, when they admit they have a problem, that's half the battle.

I tried this experiment a couple of years ago, just for schlitz & giggles. Never got even a hint of germination....

I've also tested it, and it didn't work.

I think it's possible it might work if the freezer isn't very cold at all, but I haven't tried that (although I've noticed no lack of germination in overwintered fruits that probably froze while they were whole--which is the reason for this hypothesis, since freezers tend to get a lot colder, and more consistently so, than our winters). If my hypothesis is correct, than you could probably keep selecting for cold-tolerance until you've bred tomatoes that can withstand that. Even if it's false, you could still do that through a much more laborious process, though.

Freezing dry seeds works just fine (so you might be able to salvage pepper seeds in frozen fruits, since they're not as wet), but frozen tomatoes, probably not. My efforts to germinate seeds from frozen fruits weren't extensive; so, I'm not going to rule out the possibility that some seeds of some varieties might survive. But I haven't heard any encouraging results from anyone on the topic in past discussions. Nevertheless, I still have a bunch of untested seeds that I've saved from frozen fruits.

Shule wrote: ↑Mon Jul 26, 2021 5:48 pm I've also tested it, and it didn't work.

Freezing dry seeds works just fine (so you might be able to salvage pepper seeds in frozen fruits, since they're not as wet)

Funny you should mention that, as I have germinated pepper seeds from frozen peppers. And I figured that their relative dryness was probably why they worked, but tomatoes didn't.

I was thinking about it just today, how tomato plant susceptibility to various funks and rots is an adaptive advantage to them. They don't care about keeping the fruit pristine once it starts to ripen! Moldy leaves are the perfect covering to wrap around a fruit that needs to rot before it freezes solid.

This won't work due to the formation of ice crystals inside the tomato seeds as the tomatoes freeze. These crystals puncture the cell walls, allowing cell contents to leak out, killing the seed. Pepper seed, being dry have a much greater chance of survival.

I think the problem here is that a freezer is quite a bit colder than the soil temps of those volunteer seeds. I have had volunteers only from seeds from manure, protected by the heat of the manure. Quite cold winters, at least -15C for a while.
I think MissS is right about the fruit protecting partially the seed from freezing, in the late autumn the fruit can have some considerable amount of sugars, and if the fruit partly dries off the plant, like I would imagine, than the protection will be much bigger still.

I agree, it won't work. I froze my little brother once, and he was never the same afterwards!