Kabby - if you read what the suppliers say to do, regarding storing dahlias, you'll be more confused than ever! Some wash, some don't, while some keep them upside down (to drain them of water) for two or three days and others drain them for 7 days or more.
You may want to contact the closest dahlia group to you, or your County Extension Service, to get their methods.
http://www.dahliasocietyofalab...
Your tubers will likely double if you don't dig them so you'll face having to dig just to separate them or they become huge and difficult to cut apart. They can't get enough food to keep them healthy when they get too big and the only way you'll know is by digging.
