Dahlias clean out, tie up and fertilize

The first frosty nights end this year's dahlia bloom, signaling that it's now time to dig up the tubers and put them away for frost-free winter storage.

From mid-May, the frost-sensitive dahlias can be safely planted outdoors. They prefer a deeply loosened, well-fertilized bed, because as so-called heavy growers, which form a lot of leaf mass within a short time, dahlias need sufficient nutrients.