Gardeners in southern Iowa can plant a few days earlier. Wait several additional days in northern areas. A frost or freeze can damage or destroy the plants. Dahlias perform best in full sun and a well-drained soil. Avoid wet poorly drained soils as tubers may rot.
Tubers radiate out from the dahlia crown like the spokes of a wagon wheel.
Viable tubers must have an eye originating from the crown portion, plus a neck that connects the crown to the body of the tuberous root. Before planting, drive a support, such as a metal fence post stake, wooden stake, or other device into the ground. Placing the supports into the ground prior to planting ensures that the tubers will not be impaled. Dig a hole on either side of the support. Place the tuber horizontally in the ground about 6 to 8 inches deep.