Dahlia Tuber Storage
Here at Woodend Flower Farm I store my tubers in slightly damp vermiculite, in either styrofoam boxes with the lid slightly open, or in fold down crates with a styrofoam lid placed over the top. This keeps my storage medium slightly humid, which most cultivars have proven to need. When the medium dries out too much for some cultivars they will shrivel and dry out too far, particularly any long skinny tubers, or ones with thinner necks.
After many years of trying different storage methods, this has proven to be the most effective in my cold climate.
When I ship tubers, I send a small amount of this storage medium with each tuber, however not enough for them to be stored this way until planting. You will need to emulate slightly damp storage conditions until you plant, either in vermiculite, or potting soil.
If you are in a warmer climate and your last frost date has passed - your tubers are ready to be planted on arrival.
If you are in a colder climate, your tubers will need to be stored as above until your last frost date has passed. In VIC that is typically early November (although I often wait until mid November here in Woodend).
Please visit my Dahlia Growing Guide for planting tips.

An example of tubers with eyes
The tuber on the left has a bulging eye - which is easy to spot.
The tuber on the right has a shoot and a dormant eye (circled).
Many tubers I send out have dormant eyes, they will wake up as the weather warms and turn to bulging eyes and then shoots as they begin to grow. Some dahlia cultivars can also look like they have no eyes at all when they go dormant!