Here are some other blogs from dahlia growers and various dahlia clubs. They contain loads of information on propagation, growing dahlias for show, storing tubers over the winter, etc.
Lynch Creek Dahlias:
http://www.lynchcreekdahlias.com/
The Rochester Dahlia Society (referred to as RDS in this blog):
http://rochesterdahliasociety.blogspot.com/
The Dahlia Society of Ohio (referred to as DSO in this blog):
http://dahliasocietyofohio.org/
Virginia Cooperative Extension article on the production of dahlias for cut flowers:
http://pubs.ext.vt.edu/2906/2906-1384/2906-1384.html
