If one digs in the morning and leaves the clumps out for a couple of hours, the tubers will be much less fragile. After a couple of hours, one can remove the dirt with less opportunity of breaking fragile tubers. When ready to clean the clump, use a garden hose to wash away as much dirt as possible. At this time, the clump is ready for cutting. Cutting clumps presents another tradeoff.
Many growers divide their roots in the fall.
Gardeners generally have more time in the fall than spring, and it is easier to remove dirt from and apply fungicide to divisions than to clumps. Growers uncertain about finding the eyes can cut off the tops several days before planning to dig so the eyes will have time to become more visible. If a variety's tubers are hard to keep or it makes tubers with especially thin necks and small crowns or especially small, thin tubers, then those lacking extensive experience may wish to divide the clump into sections and leave a few tubers together. Another suggestion for varieties whose roots are difficult to keep is to grow the plants in pots. Keep a rooted cutting or tuber in a 4 inch pot, plant the pot so the top is about an inch below the ground, and then treat the plant the same as any other dahlia in the garden.