Provided that your season is long enough, you could pick the first green peppers, and let the next batch ripen... but keep in mind, the peppers will need warm weather to ripen, and might not get it late in the season. You could let the first batch ripen, and once picked clean, the plants should set a second crop. Or... you could compromise. Pick all peppers but one from each plant, and let only that one ripen. A single bell pepper produces a lot of seed. If kept watered, in spite of the ripening pepper, the plants should still produce another crop. You can have your cake (or peppers) and eat it too... including the ripe peppers you saved seed from. I recommend this method because the first fruits are generally the largest (with more seed), and because seed saved early in the plant's life cycle tends to be more viable than seed saved later. This is the part you might not want to hear. Peppers can cross fairly easily, so if other peppers were grown nearby, the seed might not be pure. The results could be very unpredictable, especially if you (or a close neighbor) grow several kinds of peppers. It's very easy to isolate pepper plants for seed saving. Since the flowers self-pollinate, covering the plants with an insect-proof barrier will result in pure seed (for any flower set under cover).

Since pepper flowers are capable of pollinating themselves, chaances are they they get pollinated soon after they open, before a different cultivar can cross with them. It is already fairly rare. To guarantee that crosses do not occur, you can bag the blossom with any number of materials. I have heard of people making little bags out of toole (a type of fine netlike fabric). You could probably also use some sort of women's nylons. Don't use a plastic bag though, as it may overheat and it traps moisture. As soon as the flower shows signs of a pepper, you can remove the bag, just mark the pepper to ensure you remember which one it is.

If it's a full sized green pepper then most of the seeds will be viable. Since it ripened within a week of purchase then i'll guess it was mature enough. The ones that dry up to a dark brown/black color are probably the immature non-viable seeds, i usually throw those out.

Image by: wintersown There's two ways to save pepper seeds. You can save them from dried peppers or you can save them from fresh peppers too. You need red peppers as they are the ripest and the seeds are generally mature in them. To save them from dried peppers: I take the ripe peppers and place them uncovered in single layers on paper plates. I then put them in a warm and dry location and let them air dry for a period of a few weeks, the peppers and their seeds inside will dessicate (dry out). When the pepper is quite dry and leathery it is ready and can be saved for cooking, or you can give them as holiday gifts for cooks. You run a needle and thread through the dried pepper and tie it onto a gift package as a decorative ornament. You can store the peppers threaded and hung together on a string. The seeds can be then collected when the pepper is cut open and used for cooking. (If you live in a warm and arid climate you can string the ripe peppers together while they're fresh and hang them outdoors to allow them to dessicate in the warm breezes. ) To dry the seeds of ripe fresh peppers cut open the pepper and remove the seeds from the inner white membrane using the end of a kitchen knife to scrape them from the membrane. Place the seeds on an open plate and let them dry for a few days in an out-of-the-way safe location. Stir them every now and then to assure that the bottom layer of the seeds is exposed to the air and that the seeds are evenly dried. After they dry you can store them in paper packets. I urge you to please be cautious when working with hot peppers. Wash your hands several, SEVERAL times with a good strong detergent after touching hot peppers or their seeds. The capsicum oil in the hot peppers can burn the soft tissues of your body, it will hurt very badly if you accidently rub your eyes and that capsicum oil is still on your fingers. You may also use disposable gloves when preparing hot peppers, toss them in the trash after your done in the kitchen, and then wash your hands thoroughly afterwards. Good luck with your peppers seeds! Trudi