General Information

General growing information

Tubers begin to form in August but bulking is greatest in September, October, and November. The minimum vegetation period is 160 days.

The upper parts of the plant (stalks & leaf) do not suffer from any pests or diseases apart from early slug or snail feeding damage. The stalks of the vegetation tops of the caudices branch out in all directions above the ground and the leafage is abundant. Their growth is particularly intensive from mid-August, especially if watered.

The phenological sign for tuber bulking is when orange flowers begin to appear on the tops of the stalks. It is advised to postpone harvest as far as possible, as the edible tubers of Yakon gain the most weight at this time.

The edible tubers are fragile and require very careful handling during extraction from the ground to eliminate mechanical damage. Moreover, they break easily during handling. The stalks should be cut and removed, whereupon the tubers can be extracted, separated gently into edible spindle tubers and vegetative tubers.

General Yakon information

Yakon (Smallanthus sonchifolius), formerly Polymnia sonchifolia or Polymnia edulis is a plant from the family of Asteraceae. It is indigenous in South America, where it used to be grown everywhere, including regions formerly inhabited by the now-extinct Incas, since ancient times for its sweet, crispy and refreshing tubers. Since multiplication is done vegetatively, the plant was brought to Europe only as late as mid-19th century. Following successful introduction in France, Yakon was then cultivated in Italy and later in Germany. Since the end WWII, the plant was almost forgotten. After recent successful recent breeding and acclimatisation good yields of tubers have been achieved. However, the plant is very sensitive to frost, so cultivation is limited to certain altitudes and the vegetation period from mid-May until first freezing temperatures in the Autumn. The plant forms two types of tubers at the base of its stalk. Closer to the ground surface, the stalk produces vegetative tubers, which are not suitable for consumption.

Below these caudices, deeper in the ground are spindle-shaped tubers. Their number ranges from 7 to 14 tubers per plant and their thin skin quickly turn dark red when exposed to air. Underneath the skin is a thin layer that vaguely resembles resin in flavor and glossy flesh of crispy consistency and pleasant, fruity flavor.

Oligosaccharides and fructans activate bifidobacteriae and suppress putrefactive processes in the bowels. Improvement of the intestinal microflora reduces the content of cholesterol, triglycerides, fatty acids in the blood, and reduces blood sugar and blood pressure. Red Yakon contains nearly as much polyphenol as red wine.

The stems & leaves contain protein levels of 11-17% and can be fed to livestock.