You need to let the foliage ripen (flop and turn brown) before digging them. I have much better luck with digging the bulbs and replanting them where I want them than I do with summer storage. I have tried storing them in a cool dark place with plenty of air circulation, etc., but inevitably I lose probably 20 percent of them. When I re-locate them, virtually all will survive, and most will bloom the first spring. I will watch this post, to see if someone has a better way for summer storage.