Halfdan is a modern, auto-flowering strain derived from the crossbreeding of AK47 and Ruderalis. Due to the nature of its development, the specific origins and historical background of the strain are not documented. As a modern automatic variety, it is designed for cultivation in both indoor and outdoor environments, offering an easy difficulty level for growers, though it consistently produces a low yield over an 85-day flowering period.

The terpene profile of Halfdan is confirmed to span a complex spectrum, starting with myrcene as the primary, followed by caryophyllene, limonene, pinene, terpinolene, linalool, beta-pinene, humulene, nerolidol, ocimene, bisabolol, guaiol, camphene, caryophyllene-oxide, and p-cymene. This diverse chemical composition influences the sensory experience, providing a nuance defined by these specific aromatics. Because of the broad range of these compounds, the aroma and flavor profile tends to reflect the sequential dominance of these fifteen distinct terpenes.

As a THC-dominant cultivar, Halfdan produces effects characterized as relaxed, happy, and uplifted. These properties make the strain a suitable choice for users seeking relief from stress and pain, and it is often utilized to assist with sleep. At this time, there are no recorded offspring attributed to Halfdan, solidifying its place as a distinct, standalone entry in modern automatic genetics.