Jerusalem artichoke (Helianthus tuberosus L.) is a perennial crop native to North America and closely related to sunflower (Helianthus annuus). This species originates from the Great Lakes region, Ohio River, and the Mississippi River Valleys (Swanton et al., 1992) and was cultivated by Native Americans. Jerusalem artichoke, also named sunchoke (used hereafter) or topinambour, possesses low agronomic requirements and is currently cultivated for its diverse industrial applications.
Sunchokes are known for producing high-carbohydrate tubers containing up to 75% inulin by dry weight. The high inulin content allows sunchoke tubers to be an excellent source of prebiotic fiber, promoting beneficial intestinal bacteria growth and supporting digestive health (Shao et al., 2020). However, inulin content of tubers may vary due to several factors:
- Variety. Different sunchoke varieties can have varying inulin contents (Sennoi & Puttha, 2021).
- Growing conditions. Soil composition and cultivation practices can affect inulin content (Pinmongkholgul et al., 2021).
- Storage time. Fresh tubers usually have higher inulin content. Inulin is sensitive to cold temperatures (below 5 degrees Celsius) and inulin content decreases in cold storage conditions (Sennoi & Puttha, 2021) or after several frost events if the tubers remain in the ground.
Inulin is a dietary fiber with prebiotic activities. One of its potential health benefits includes alleviating type 2 diabetes through modulation of the large intestine microflora. This prebiotic effect makes sunchoke tubers a valuable crop for food and industrial applications.
Additionally, sunchoke shows significant potential as a biofuel feedstock due to its high biomass yields. Sunchoke tubers can produce ethanol yields comparable to or higher than crops like corn and sugarcane (producing 1,500–11,000 liters per hectare of ethanol) (Bogucka et al., 2021).
How to Grow Sunchoke From Tubers
The best way to plant sunchokes is by using tubers. This planting process is simple, but it requires the right timing and sufficient space between each plant. In U.S. climates (USDA zones 6–7), tubers can be planted from late April until mid-May when soil temperatures reach 6–7 C. The tuber should be placed approximately 6 inches deep. Depending on the sunchoke variety and soil type, a distance of 2–3 feet is required, as the plants can grow quite large. While sunchokes can grow in any soil type, the ideal soil for growing sunchokes is light-textured and nutrient-rich, which not only provides a suitable location for growing tubers but also supplies essential nutrients for plant development. This planting method allows for efficient use of space while simultaneously promoting healthy development of the plants throughout the growing season.
Water and Fertilizer
Sunchokes need regular watering inputs and a close watch on soil moisture from planting until harvest process. Using mulching, like straw, can help regulate soil moisture.
Sunchoke plants show higher yields with regular applications (biweekly or monthly) of fertilizer with a balanced nitrogen, phosphorus, and potassium (NPK) ratio (e.g., 20-20-20). It is best to monitor the plants during the growing season for signs of nutrient deficiencies, such as yellowing leaves or stunted growth. If needed, supplement the plant with additional fertilizer to give an extra nutrient boost. Proper watering and fertilizing ensure healthy sunchoke plants and maximize tuber yields at harvest time. 
Gardening
Sunchokes are full-sun crops and an excellent addition to any garden. During the growing season, they form dense bushes and produce beautiful yellow flowers. These small, sunflower-like flowers typically appear from September to mid-October, adding vibrant beauty to the garden.
The cheerful flowers not only enhance the garden's aesthetic appeal but also attract a variety of bees, contributing to pollination and biodiversity. Their ability to grow vigorously and beautifully makes them a fantastic choice for gardeners seeking functionality and charm.
Because some varieties can grow above 10 feet, it is a great idea to use wooden or metal stakes to nurture straight growth and avoid stem breakage due to strong winds or the plant’s weight. The stakes can be installed during the growing season.
Harvesting
The sunchoke harvest can be conducted in the middle of October after the first frost. Harvest should be carried out using a systematic approach:
- First step. The stems should be cut approximately 20 centimeters above the soil level to facilitate initial root-system exposure. Then excess leaves and branches should be cleared from the soil surface to establish a clean working area.
- Second step. A small shovel can be used to carefully dig around the stems, systematically revealing the underground root and tuber structures. The entire root system should be gently moved from the ground. This process can take time, as certain sunchoke varieties can produce numerous long rhizomes in every direction.
- Third and final step. A complete soil search should be conducted to ensure all tubers are collected to avoid sunchoke plants growing as volunteers the following spring.
How to Use Sunchokes
Two main types of sunchoke products exist: tubers and forage. Tubers are the more popular product and have a wide range of applications, while forage is primarily used in livestock diets, particularly for sheep (Razmkhah et al., 2017).
Uses of Sunchoke tubers
- Food Industry
Sunchoke tubers are a versatile ingredient in the kitchen and can be used in various recipes, such as mashing, roasting, soups, and even chips. As a local product native to North America, they are becoming increasingly valued for their culinary potential.
- Industrial Applications
Because of their rich chemical composition and good resistance to environmental stressors (biotic and abiotic), sunchokes serve as raw materials for producing ethanol, butanol, succinic acid, citric acid, lactic acid, and other bioactive compounds.
- Health and Medicine (Sawicka et al., 2020)
Sunchokes are rich in bioactive compounds like inulin and its derivatives, which have been researched for their potential health-promoting effects. Studies suggest that increased consumption of sunchoke products may help support a healthy lifestyle in a variety of ways:
- lower blood pressure, cholesterol, triglycerides, and glucose levels
- support weight loss and improving metabolism
- act as antidiabetic, anti-carcinogenic, anti-fungistatic, and antioxidant agents
- detoxify the body by removing alcohol, heavy metals, and radionuclides
- prevent constipation, acne, and protecting the gastric mucosa
- boost the immune system and improving gut flora health
Conclusion
Sunchokes are a valuable crop with diverse applications in the food industry, chemical production, medicines, pharmaceuticals, and livestock feed. Their ease of cultivation and affordability make them an attractive option for various industries while offering significant health benefits to consumers.
Additional Resources
- U. S. Department of Agriculture (NSDA), Natural Resources Conservation Service, plant profile database
(plants.usda.gov/plant-profile/HETU)
References
Bogucka, B., PszczóÅ‚kowska, A., Okorski, A., & Jankowski, K. J. (2021). The effects of potassium fertilization and irrigation on the yield and health status of Jerusalem artichoke (Helianthus tuberosus L.). Agronomy, 11(2), 234.
doi.org/10.3390/agronomy11020234
Pinmongkholgul, S., Ganranoo, L., Timson, Y., Jantapatak, W., & Boonriam, W. (2021). Inulin evaluation of Jerusalem artichoke (Helianthus tuberosus) from organic cultivation areas, Phayao, Thailand. International Journal of Agricultural Technology, 1(17), 627–640.
researchgate.net/publication/353820798_Inulin_evaluation_of_Jerusalem_artichoke_Helianthus_tuberosus_from_organic_cultivation_areas
Razmkhah, M., Rezaei, J., & Fazaeli, H. (2017). Use of Jerusalem artichoke tops silage to replace corn silage in sheep diet. Animal Feed Science and Technology, 228, 168–177.
doi.org/10.1016/j.anifeedsci.2017.04.019
Sawicka, B., Skiba, D., PszczóÅ‚kowski, P., Aslan, I., Sharifi-Rad, J., & Krochmal-Marczak, B. (2020). Jerusalem artichoke (Helianthus tuberosus L.) as a medicinal plant and its natural products. Cellular and Molecular Biology, 66(4), 160–177.
doi.org/10.14715/cmb/2020.66.4.20
Sennoi, R., & Puttha, R. (2021). Inulin content of Jerusalem artichoke (Helianthus tuberosus L.) tubers stored at 5 °C refrigerator for different durations. Australian Journal of Crop Science, 15(12), 1395–1398.
doi.org/10.21475/ajcs.21.15.12.p3158
Shao, T., Yu, Q., Zhu, T., Liu, A., Gao, X., Long, X., & Liu, Z. (2020). Inulin from Jerusalem artichoke tubers alleviate hyperglycaemia in high-fat-diet-induced diabetes mice through the intestinal microflora improvement. British Journal of Nutrition, 123(3), 308–318.
doi.org/10.1017/S0007114519002332
Swanton, C. J., Cavers, P. B., Clements, D. R., & Moore M. J. (1992). The biology of Canadian weeds. 101. Helianthus tuberosus L. Canadian Journal of Plant Science, 72, 1367–1382.
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