In all the years we have been growing vegetables for sale we have seen a lot of our favorite seeds disappear from the marketplace. They are replaced often by something that doesn't grow as well for us. The solution is to grow our own seed of varieties that are particularly valuable to us. Or, we find an unusual chard or kale or bean and want to see if we can develop that characteristic in a new strain. Above Joel is removing the seedpods from some overwintering purple sprouting broccoli. This seed is hard to find in this country as it grows best in Britain and in climates like ours which is similar.
Large seed operations need a lot of fancy equipment to clean and process seed but for a small bunch for our own use the old fashioned way of winnowing by pouring the seed and trash from one container to another in a stiff wind works just fine. The lighter bits of seedpods and stems blow away and the heavier seeds fall into the lower bucket.