I guess the first thing to ask is: When are you harvesting the seeds? Are you letting the pods go the recommended 6 weeks before harvesting the seeds? Are the seeds dark, plump, shiny and black? Are they of varying size from the same pod? All these things will have an influence on the viability of the seeds, and therefore will determine if the seed rots, or not. Keep track of when you make the crosses so you know how old the pods are. In week five, start looking at the pods. If the pods are getting brown---are the brown areas dry, or wet? If dry, that's OK--they can go longer. Many cultivars will only set seed in one or two of the 3 to 4 chambers of the pod. Many times the plant will shut off nutrients and water to those chambers, and they will dry---while the other chambers stay green. As long as the dry chamber does not start to rot when wet (rain), it will not effect the rest of the pod. If it stays wet after a rain storm, and feels slimy to touch---especially if it smells bad, the pod needs to be harvested. If the pod is at least 5 weeks old, set it somewhere where it will dry for a few days before opening the green chambers. If the seeds that come out at that time are as described earlier, then give them the squeeze test.
The squeeze test is pretty simple. Take each seed between your thumb and forefinger and give it a gentle, but fairly firm, squeeze. If you detect any give to the hull---like squeezing a rubber ball---the seed is probably not viable. The best seeds are the ones that have no "give" to them---they are hard and shiny black, and can withstand a pretty hard squeeze before bursting. (This takes some practice. Test this on some seeds that are not the ones you want to save before you start to squeeze your prized ones.) However, there is some gray area to this evaluation. There are rare cultivars that produce seeds that are never hard and shiny. I have a great pink cultivar that is a seedling produced by Stoeri that routinely opens the pod on week four or five, produces elongated, soft, wrinkly (they look like skinny raisins), dark brown seeds that are extremely viable. On the other hand, I have a plant that routinely produces seeds at week 6 that are hard and shiny--and pass the squeeze test, but are brown in color and do not germinate. These examples are the rare exceptions--not the norm. Color and hardness are the best predictors of viability.
I let the seeds dry for two to three hours (I have the cat problem, too) and then put them in plastic snack baggies that I get from Lowe's Food. I have tried the ones from Food Lion, and other grocery stores, but the ones from Lowe's are a bit sturdier, seal better, and allow drying better than the others. In the bags with the seeds goes a piece of copier paper approximately 2" x 3.5" upon which is written the name of the parents of the seeds, i.e.: Blue Pink Beauty x Bella Sera. I use the whitest, thickest, most high quality typing/copier paper I can find. The reason for that is that that kind of paper has the highest amount of residual chlorine left in it. The chlorine acts as a disinfectant that helps prevent rot. It also absorbs excess moisture from the seeds and distributes that moisture over a larger area in the bag. I store the bags in paper lunch bags in a refrigerator that is set at 45 degrees. I check the seeds after a week or two. Some seeds are pretty moist when harvested (especially if it rained the day before, or the day of---harvest). In those cases there may be visible water in the bag, or a moist area on the paper that is more than 1/2" in diameter. This can also happen if there are too many seeds in one bag. I generally place no more than eight seeds/bag to prevent this from happening. If there is only a small moist, but not wet area on the paper, I will rearrange the seeds in the bag to get them on a drier area of the paper.
A little moisture in the bag will keep the seeds viable in storage longer. Also, many times, it will decrease the need for stratification of the seeds before planting. If you know that stratification is needed for some seeds (both parents are Hard Dormant varieties), it is easy to do. Just add a few drops of sterile water to the seeds in the bag a couple of weeks before you want to plant them. Keep a daily watch on them to see when the husk starts to break open and the root just starts to emerge from the seed. That seed will need planting right away. Daily watching will also detect any rot that starts up on one or more of the seeds that could threaten the viability of all the seeds. The white paper in the bag with the cross name on it serves another purpose at this time. If the moisture around a seed has a brownish hue to it, open the bag and inspect the seeds---especially that one. It may be starting to go bad, and can be removed.
Seeds processed and stored this way have retained as much as 50% viability after three years. So---that great cross you made last year that you just did not have the room to plant then---go ahead. More than you think will germinate. I hope this information has been helpful.
