The safest and easiest way is to bag the blossom before it opens. You can make your own bags out of material like tulle - something that lets the air circulate but keeps out the insects that could cause cross-pollination - with a drawstring to tighten around the branch. I buy those little organza wedding/party gift bags with drawstrings from wedding/party supply shops.

Trim away foliage from around the target blossoms so you won't end up with foliage growing inside the bag and cramping the blossoms. Bag the blossoms before they open, before the yellow is visible. As soon as fruit has set, when the chance of cross-pollination has passed, you can remove the bag. Nip off any blossoms that were in the bag that haven't opened or didn't pollinate. Tie something like a piece of coloured string to the stem of the bagged fruit to identify it as having been bagged. It's too easy to lose track of unmarked fruit as the plant grows.

Simple as that!

What happens after that?

Raymondo said something on another thread that he buys tomatoes for their juice if his don't have enough so there must be more to this than spitting the pips into a paper towel. :)

Amanda

After collecting the seeds, ferment them. Have a look at the ISSI web site for a good set of instructions.

If I'm saving seeds from, say, one single tomato, and there's not enough juice to cover the seeds, I add a teaspoon or so of water.

Amanda, I use sherry or shot glasses for fermentations unless there's going to be a lot of seeds with their gel and tomato juice. Generally I'm only processing one large tomato or 2 to 3 medium ones, or maybe 6-8 cherry sized ones at a time tho. There should be enough juice to prevent the seeds from drying out. Personally I don't add water because it seems to slow the fermentation process. I like Ray's idea of using the juice from supermarket tomatoes if necessary, because it at least is something useful they can do, since eating one would just put me off tomatoes, full stop!

At first you'll notice that the seeds tend to clump together at the top of the fluid, but (depending on the weather) after 2 or 3 days you'll see that some are starting to fall to the bottom of the glass. If you tap the glass, others fall too. That means the gel has broken down and you can start rinsing to get rid of the crusty fungal top layer and all the fibrous junk.

I dump the contents into a large glass for rinsing so that I can use a bit of pressure from the tap to clean off the debri. The seeds are generally nice and clean, but if not, then I tip the contents into a fine mesh tea strainer and stir around with my finger to mush up the clingy stuff, then rinse again and spread the seeds to dry. I generally try to spread them in a single layer for even drying.

Whenever I get around to it, I store the seeds in paper envelopes at room temperature for the first year, plus I put all of last season's seeds into a large ziploc with a bit of silica gel and store them in the fridge before the next season begins. Always let seeds come to room temperature before opening them tho, to avoid condensation. If you need to get into the packets often, it would probably be simpler to just store them in a cool dark place in your coolest room of the house.

PP

On occasion, I've thought fermentation was finished, but when I started rinsing, I realised it wasn't. Extra, fresh tomato juice is very useful in this situation because the original mixture has become too diluted to work. It's also very handy if someone gives you a bunch of seed wrapped in a tissue, still covered in gel, which has happened to me a few times.