Having selected one or more tubers, separate them from the stem using a sharp knife or large pair of scissors. The aim is to achieve as clean a cut through the stem as possible. Each separated tuber must include a part of the main stem.

The dahlia picture on the left shows a selected tuber separated from the stem, but with a piece of the stem still attached. It's important to keep a part of the main stem attached to the tuber because the area around the stem and the top of the tuber is where eyes will sprout. Remove all excess material from the tuber.