The Three Sisters of Indigenous American Agriculture

According to Chavonda Jacobs-Young, Ph.D. Administrator, Agricultural Research Service. U.S. Department of Agriculture, "in agricultural parlance, 'The Three Sisters' are crops planted together in a shared space: maize, beans, and squash…. Developed through [I]ndigenous agricultural practices, these three plants protect and nourish each other in different ways as they grow and provide a solid diet for their cultivators."

The intercropping method of planting corn, beans, and squash together, commonly called The Three Sisters has been studied and described by scholars in anthropology, history, agriculture, and food studies for many  years. While this practice is often cited in current sources as a way to improve small gardens for individual use, its historical value lay in larger-scale implementations designed to nurture and sustain entire communities.

The great majority of this research has been created by scholars who were not members of the Indigenous communities which originally developed and maintained this tradition. Thus, this short review will strive to elevate Indigenous authors and practitioners whenever possible, while acknowledging the bulk of the available publications originate from work that did not center their voices.

The Three Sisters model was not just a means for modeling a specific intercropping practice but was, and is, a significant cultural and spiritual construct.

Diohe'ko, the Three Sisters, had been cultivated for at least five hundred years prior to contact by the Seneca, an Iroquoian tribe inhabiting western New York State. The Three Sisters, corn, beans and squash (pumpkins, gourds), were planted together in hills in fields, cultivated and harvested by work parties of women….The Three Sisters was an important cultural complex. The Sisters are protagonists of a number of Seneca tales, myths, ceremonies and legends. p. 76

Lewandowski, S. (1987). Diohe'ko, the Three Sisters in Seneca life: Implications for a native agriculture in the finger lakes region of New York State. Agriculture and Human Values, 4, 76–93 (1987). https://doi.org/10.1007/BF01530644

The Carnegie Museum of Natural History broadens the classification from the specific Seneca Nation to that of the Haudenosaunee (Iroquois) Confederacy in its description of the Three Sisters.

To the Iroquois people, corn, beans, and squash are the Three Sisters, the physical and spiritual sustainers of life. These life-supporting plants were given to the people when all three miraculously sprouted from the body of Sky Woman's daughter, granting the gift of agriculture to the Iroquois nations.

Carnegie Museum of Natural History. (2018). The Three Sisters: Sustainers of life. https://nsew.carnegiemnh.org/iroquois-confederacy-of-the-northeast/three_sisters/.

The Carnegie Museum of Natural History also provides a useful description of just how this method was carried out.

The Iroquois agricultural system was based on the hill-planting method. Iroquois women, who were responsible for farming, placed several kernels of corn in a hole. As the small seedlings began to grow, the farmers returned periodically to mound the soil around the young plants, ultimately creating a hill one foot high and two feet wide. The hills were arranged in rows about one step apart.

Iroquois women mixed their crops, using a system called "interplanting." Two or three weeks after the corn was planted, the women returned to plant bean seeds in the same hills. The beans contributed nitrogen to the soil, and the cornstalks served as bean poles. Between the rows, the farmers cultivated a low-growing crop such as squash or pumpkins, the leaves of which shaded the ground, preserving moisture and inhibiting weed growth.

Carnegie Museum of Natural History. (2018). The Three Sisters: Sustainers of life. https://nsew.carnegiemnh.org/iroquois-confederacy-of-the-northeast/three_sisters/.

Some Indigenous Peoples of the Americas planted corn, beans and squash or pumpkins together in mounds, in an intercropping complex known to some as the Three Sisters. Corn provided support for beans, beans provided nitrogen through nitrogen-fixing rhizobia bacteria that live on the roots, and squash and pumpkins provided ground cover to suppress weeds and inhibit evaporation from the soil. While the origins of the Three Sisters complex are unknown, veneration of the Three Sisters appears in the earliest accounts of European explorers and missionaries in North America. As described by Lewandowski, from its earliest appearance in written records, the Three Sisters complex was not simply an agricultural strategy or technology, but a cultural complex, complete with stories, ceremonies, technology, customs and etiquette.

Archaeological evidence dates the adoption of the Three Sisters complex in North America to 1070 AD. The complex was adapted to local conditions over the 500 years before contact with Europeans, so much so that it was the dominant food plant association of every nation practising agriculture in the northeast USA as well as in several other parts of North America, including southern regions of Quebec and Ontario, Canada. The Indigenous Peoples practising Three Sisters agriculture in the northeastern USA and southeastern Canada included those from at least fifteen nations. p, 2

Ngapo, T.M., Bilodeau, P., Arcand, Y., Charles, M.T., Diederichsen, A., Germain, I., Liu, Q., MacKinnon, S., Messiga, A.J., Mondor, M., et al. (2021). Historical Indigenous food preparation using produce of the Three Sisters intercropping system. Foods, 10, 524. https://doi.org/10.3390/foods10030524.

This ancient style of companion planting has played a key role in the survival of all people in North America. Grown together, these plants are able to thrive and provide high-yield, high-quality crops with a minimal environmental impact. Corn, beans, and squash have a unique symbiotic relationship in a Native American garden. Corn offers a structure for the beans to climb. The beans, in turn, help to replenish the soil with nutrients. And the large leaves of squash and pumpkin vines provide living mulch that conserves water and provides weed control.

Dodson, M. (2001). Appendix: Ancient Companions. In Kuepper, G. & Dodson, M. Companion Planting & Botanical Pesticides: Concepts & Resources. https://attra.ncat.org/publication/companion-planting-resources/.

Charles L. Mohler and Kimberly A. Stoner provide a good overview of the various farming practices that are relevant to Three Sisters' farming:

Intercropping is an all-encompassing term for the practice of growing two or more crops in close proximity: in the same row or bed, or in rows or strips that are close enough for biological interaction. Mixed cropping, companion planting, relay cropping, interseeding, overseeding, underseeding, smother cropping, planting polycultures, and using living mulch are all forms of intercropping.

Mohler, C,L. & Stoner, K.A. (2009). Crop rotation on organic farms: Guidelines for intercropping. Brentwood, MD: Sustainable Agriculture Research and Education (SARE) Publications. https://www.sare.org/wp-content/uploads/Crop-Rotation-on-Organic-Farms.pdf.

Finally, a recent meta-analysis of maize/soybean intercropping concluded,

…maize/soybean intercropping is a promising practice to meet the challenge of sustainable development and food security. It is important not only for smallholder agriculture in developing countries, e.g. in Africa, to meet demands for calories and protein (Snapp et al., 2010), but also for organic farming and land sparing in developing countries (Fischer et al., 2008; Phalan et al., 2011). Maize/soybean intercropping can result in major increases in the efficiency of land and N fertilizer use, but this potential is largely untapped in contemporary farming in developed countries…. A multidisciplinary multi-actor approach will be needed, with involvement of stakeholders, to bring these potential advantages of intercropping of maize and soybean to practice.

Xu, Z., Ki, C., Zhang, C., Yu, Y., van der Werf, W., & Zhang, F. (2020). Intercropping maize and soybean increases efficiency of land and fertilizer nitrogen use: A meta-analysis. Field Crops Research, 246(1), 107661. https://doi.org/10.1016/j.fcr.2019.107661.

Yanovsky, E. (1936). Food plants of the North American Indians. U.S. Department of Agriculture. Miscellaneous Publication, Number 237. https://archive.org/details/foodplantsofnort237yano.

This publication is a summary of the records of food plants used by the Indians of the United States and Canada which have appeared in ethnobotanical publications during a period of nearly 80 years. This compilation, for which all accessible literature has been searched, was drawn up as a preliminary to work by the Bureau of Chemistry and Soils on the chemical constituents and food value of native North American plants. In a compilation of this sort, in which it is impossible to authenticate most of the botanical identifications because of the unavailability of the specimens on which they were based, occasional errors are unavoidable. All the botanical names given have been reviewed in the light of our present knowledge of plant distribution, however, and it is believed that obvious errors of identification have been eliminated. The list finds its justification as a convenient summary of the extensive literature and is to be used subject to confirmation and correction. In every instance brief references are made to the original authorities for the information cited.

Morse, W.J. (1918). The soy bean: Its culture and uses. Farmers' Bulletin, Number 973. https://archive.org/details/CAT87202617.

The soy bean may be satisfactorily grown in combination with other farm crops. Although the chief advantage, perhaps, is a better balanced ration, the results of experiments indicate a larger yield of forage, as well as a greater variety….Soy beans are more generally grown with corn than with any other crop. Various methods of growing the two crops are practiced in different areas of the country. The beans may be planted in the same hills with the corn, in alternate hills with corn in the same row, in alternate rows of each, or there may be two rows of each." p. 18

Crosby, M.A. (1918). Farm practices that increase crop yields: The Gulf Coast region. Farmers' Bulletin, Number 986. https://archive.org/details/CAT10308363.

Intercropping with legumes—that is, growing some leguminous crop between the rows of intertilled crops, such as corn or cotton—is the simplest system of growing crops for soil improvement. This practice is an inexpensive and easy means of increasing crop yields, yet, while common in many sections, is not followed to the extent that it should be. The continuous growing of any one intertilled crop on the same land for a succession of years is not good farm practice; but where this is the custom, as is the case in many sections, the practice of intercropping with legumes will frequently keep a sufficient supply of humus in the land to maintain crop yields.

Corn lends itself better to the practice of intercropping than any other crop of this region, and it is with the corn crop that the greatest possibilities are offered for soil improvement by this system. Crops used in this region for intercropping are cowpeas, soy beans, peanuts, velvet beans, and beggar weed." p. 19.

McNair, A.D. (1918). Crop systems for Arkansas. Farmers' Bulletin, Number 1000. https://archive.org/details/CAT87205204.

Crop systems for Arkansas that make for increased food productions and increased efficiency in man labor and horse labor are described in the following pages. By the introduction of cowpeas, soy beans, and other legumes, and by second cropping, provision is made for a considerable increase in the number of crop acres that can be farmed by the average family. Thus, two men with a team, who under a cotton and corn system can farm but 33 acres of land, can handle 50 acres and raise 62 acres of crops under a system providing for a 4-year rotation, including (1) cotton with a winter cover crop, (2) cowpeas, (3) oats or wheat followed by cowpeas, and (4) corn.

Hill, C.G. (2016). Pre-Colonial foodways. In Wallach, J.J., Swindall, L.R., & Wise, M.D. (Eds.) The Routledge History of American Foodways (pp. 9-22). London: Routledge Press.

Hill, C.G. (2020). Returning corn, beans, and squash to Native American farms. The Conversation. Iowa State University. https://theconversation.com/returning-the-three-sisters-corn-beans-and-squash-to-native-american-farms-nourishes-people-land-and-cultures-149230.

Hirst, K. Kris. (2020). The Three Sisters: The traditional intercropping agricultural method. https://www.thoughtco.com/three-sisters-american-farming-173034.

LaDuke, W. (2005). Recovering the sacred: The power of naming and claiming. Cambridge, MA: South End Press. https://archive.details/recoveringsacred00ladu.

Landon, A.J. (2008). The "How" of the Three Sisters: The origins of agriculture in Mesoamerica and the human niche. Nebraska Anthropologist, 40,110‐ 124. https://digitalcommons.unl.edu/nebanthro/40.

Lopez-Ridaura, S., Barba-Escoto, L., Reyna-Ramirez, C. A., Sum, C., Palacios-Rojas, N., & Gerard, B. (2021). Maize intercropping in the milpa system. Diversity, extent, and importance for nutritional security in the Western Highlands of Guatemala. Scientific Reports, 11(1), 3696. https://doi.org/10.1038/s41598-021-82784-2.

Lunsford, L., Arthur, M. L., & Porter, C. M. (2021). African and Native American foodways and resilience: From 1619 to COVID-19. Journal of Agriculture, Food Systems, and Community Development, 10(4), 241–265. https://doi.org/10.5304/jafscd.2021.104.008.