I thawed two different tomatoes, one from each of my two freezers, and extracted seeds. (The varieties were Post Office Spoonful and Butter Apple. They were planted in my seeding tray like any other tomato seeds. After a month, there was no germination. It's looking like once the fruit is frozen, the seeds won't sprout.

This is in contrast to Shule1's situation, where his Galapagos Island tomato plant was exposed to sub-freezing temperatures but several fruits did not freeze. Seeds from those fruits did sprout.

Thanks for reporting back on this experiment.
Curious minds wanted to know!

Glad to hear you tried this, Nan. I thought this might be the case, but you never know for sure til you try.

From what I have learned, a fully cleaned and dried out seed is ok to freeze and will germinate, but one with water attached in the form of tomato pulp or seed gel will just become frozen and die. I haven't tried it out.

A friend of mine usually stores tomato seeds in his freezer.

I also have few positive experiences with seeds from frozen tomatoes.

Hi Nan! Great to hear the results of your experiment. Good point about Shule's seeds too - can still get viable seeds from tomatoes touched by frost vs those that got the deep freeze.

@Bower

Although it wasn't as cold as a freezer, it was considerably more than a light frost!

They got to down to as low as 18° F. (not sure if it got that low, but probably not lower), and definitely as low as about 22° F. lots of times over and over for a long period; it did have warmer periods in between). For some reason, those particular fruits still seemed as if they hadn't ever been frozen, however. Frost can happen when it's up to 41° as reported on the weather (but it's really about 32° F. or lower on the ground during those times when it frosts above freezing, as I understand it; they take the temperature higher in the air where it's potentially warmer than the plants).

Morelle De Balbis is a related species to tomatoes. I think it's interesting that its fruit gets destroyed before the Galapagos Island tomato fruit seemed to this year (but the plant itself for Morelle De Balbis survives much colder temperatures than any tomato I've tried).

I read somewhere that you can cross goji and tomatoes together (and/or vice versa; not sure which). That might be a way to get something like a cold-hardy tomato. I'm not sure which goji species it was.

Is goji a Solanum?

Had some well cured seeds get to 30 below F and they sprouted.

In my experience, dry frozen seeds will germinate. If the seeds are still moist when frozen, the liquid expands and cracks the seed coat and thus the seeds are destroyed.
Even outdoors here were it gets -20 degrees, I can have volunteers from seeds that have frozen. The difference between those that survive the winter and those not is that the former seeds are from dried up fruit.

[mention]Nan6b[/mention]

Is goji a Solanum?

No, but they are in the same family. It's one of those rare situations where sort of distant species can cross. Sheep and goats are like that (but hybrids are extremely rare, and said to be sterile, although I'm not sure how they figured that out). I'm not sure how easy it is to cross tomatoes and goji.

In theory, a higher brix in a tomato should mean a lower freezing point. Brix isn't just sugar, though (well, according to one source; maybe others just call what I mean TDS: total dissolved solids). It can be acids, mineral salts, and probably other stuff. I didn't water my plant very much; so, it's possible those things were pretty concentrated. Solanum cheesmaniae is supposed to be salt-tolerant, too; maybe it absorbs more salt. There probably were plenty of minerals in the soil for the plant to use (I gave some magnesium/zinc/copper/iron to watermelons that were growing there in 2018). The water it did get was chlorinated. So, the salt index may have been high in the soil.

However, it's worth noting that many of the other tomatoes had the same sort of soil and watering, and they didn't fare as well in freezing weather (they also weren't as prolific; so, maybe there were just fewer candidates for withstanding the temperatures). I didn't test germination rates of fruits that had obviously frozen, though.

I've wanted a refractometer for a long time, but it looks like TDS meters are less expensive. I wonder if they work on tomato juice.

This site claims you can use a TDS meter to measure nutrients in plants.

I guess they have cheaper refractometers than the last time I checked. Specific gravity appears to be another thing one might want to test.

I replied to this thread yesterday, but it is gone.

Tomato seeds can be frozen IF they are dried. If they are wet the water expands and cracks the seed coat and perhaps the enclosed embryo as well which makes the seed non-viable. I also get volunteers each year. These are from fruits that were dried up naturally before winter.

[mention]MissS[/mention]
Your old post is still there. It's #752.

This site numbers each post? That number is going to balloon up fast.

Interesting topic. I'll be making chili sometime this week using my frozen tomatoes from 2019. My wife tends to just cut them up and throw them in ziplock bags, so there will be plenty of seeds. I remove as many seeds as possible before cooking anyway...How many to plant? Would 20 or so be enough of a sample?