Yes, you are missing a couple of steps that will ensure germination next year. Here's what I learned as a newbie to heirloom seed saving (as far as I know only tomatoes need this treatment).

Green tomatoes are not ripe and therefore neither are the seeds. You need a tomato way past prime for viable fertile seeds. If you picked the green tomatoes and let them ripen inside the house, the seeds will still not be viable. Can you leave a tomato or two on the vine to hope that they turn red and mature? Are there any rotten ones on the ground you can collect seeds from?

To dry tomato seeds to plant next year you will need to ferment them so that the nearly invisible coating is removed. Put seeds and the clear pulp from around them in a small cup. Add a little water and let them sit at room temp for 3 days. You will see scum on them. Rinse the seeds in a very fine sieve like you'd use for loose tea. Put the seeds back in the rinsed cup and pour in a little fresh water. Wait another 3 days. If you still see scum, repeat rinse steps for another 3 days until no more scum appears. Now lay them out on a sheet of paper towel and let them air dry for a few days. Scrape them off the paper towel and into a zippered sandwich bag, or snack bag. Make sure you label what is in the bag with the name of the heirloom tomato along with the date. To make sure the seeds stay dry, make a packet by stapling a small piece of paper towel filled with some instant powdered milk. Put the stapled packet in the bag with the seeds. Any moisture will be absorbed by the milk powder not the seeds. Store the seed bags at room temp someplace dark.

It takes more time to type the instructions than it does to actually do it.

Nancy the nancedar
- who has more than 100 little seed bags waiting for next year.

Thank you!! Actually, I have one tomato that looks like it's turning red. I'll let it stay there and fully ripen. I can also let the others stay put too.

Thank you!! At least if I start the collection process properly, I'll be better off come sowing time.

Nan, i've found you don't even need to ferment the seed. When i went to tomatopalooza a few years back i slathered some seed from the ones i liked onto index cards, wrote their name on them, folded them in half, slipped them into plastic bags (about 10 cards to a bag)then let them dry by leaving the bags mostly open. They sprouted with no further ado the next year. They'll be stuck to each other and the card- to get them off, just pry the ones you need off with your fingernail. The others can stay stuck to the card til you need them. It will get black and moldy as it dries but it doesn't hurt anything.

Tomatoes are great because if you keep them cool and dry (room temp is fine, fridge is better), they'll keep and germinate for 10+ years.

I scrape them out onto a paper towel and leave them out to dry for a few days. Then I plop the whole thing into a plastic storage bag. Just like Tamelask says..you just scrape em off when it is time to plant. I have never done the presoaking described, but I have presoaked okra and squash seeds, I guess it wouldn't hurt to presoak these. If they don't ripen, looks like either fried green tomatos or pickled green tomatos are in your future

I agree with the above except the fruit don't have to be "Way past ripe to be viable". Just ripe is just fine. I start 20 - 30 different varieties each year from seed. I do ferment my seed. It may kill off a few pathogens and the clean seeds don't clump together as much. Presoaking isn't necessary the first few years, but as the seed gets older soaking with a tiny bit of MG can help. My personal best for older seed is 17 years. Have fun.
Jim

Wanted to mention, i've opened tomatoes for canning that weren't overripe or fermenting and found germinating seeds in them! Maters are one of the easiest things to gather seed and start it growing in my experience.

If you have difficulty getting good germ rates i've found that sandwiching a few seeds in a moist paper towel in a plastic baggie that's set somewhere warm like the top of the fridge, really speeds things up and lets you determine if the seed is still viable.