How are Dahlias measured?
Dahlias are measured by the weight of the tuber. The tuber is weighed after the grower harvests it and prepares it for us. A #1 Dahlia (a very good size!) must weigh a minimum of 90 grams at time of harvest.
A #1 Dahlia will have more sprouts at the base of its stem (crown), giving you better results growing it in your garden. You end up with fuller plants and more flowers when you start with a #1 Dahlia.