24/11/2011 at 15:28
The danger with leaving them in the pot is that they will rot. What I would do is remove the dahlia from the pot, cut off the stem and dry the tuber as described in the article. Once dry place the Tubers in a tray/pot and cover with dry compost. Then watch Sarah's video on taking cuttings. From my experience taking cuttings is a guaranteed way of increasing your stock of Dahlias for free!