Reuniting the Three Sisters: Native American Intercropping and Soil Health

Project Overview

Project Type: Research and Education
Funds awarded in 2019: $200,000.00
Projected End Date: 12/31/2022
Grant Recipient: Iowa State University
Region: North Central
State: Iowa
Project Coordinator:
Dr. Christina Gish Hill
Iowa State University

Information Products

Three Sisters Gardening Project (Article/Newsletter/Blog)
Recovering Indigenous Agriculture (Article/Newsletter/Blog)


  • Agronomic: corn, sunflower
  • Vegetables: beans, cucurbits
  • Additional Plants: native plants


  • Crop Production: intercropping, seed saving
  • Education and Training: extension, on-farm/ranch research, participatory research, workshop
  • Natural Resources/Environment: carbon sequestration, soil stabilization
  • Soil Management: soil quality/health
  • Sustainable Communities: ethnic differences/cultural and demographic change, local and regional food systems

    Proposal abstract:

    Reuniting the Three Sisters explores the cultural and agronomic underpinnings of the Native American practice of intercropping corn/maize (Zea mays), common beans (Phaseolus vulgaris), and squash (Cucurbita moschata)—colloquially called the Three Sisters. Because Native American communities in the Midwest have limited access to healthy, fresh foods, Native growers have established community gardens to incorporate culturally appropriate Indigenous growing practices, including the Three Sisters, to build community and improve health. Yet, support systems for these gardens remains inadequate. Thus, there is a critical need to determine the production barriers that Native gardeners experience and design research that demonstrates ways to improve soil/plant/human health. Without such knowledge, developing culturally appropriate agronomic strategies to help increase community gardening in Native communities will remain stymied.

    This project documents cultural and agronomic underpinnings of Three Sisters intercropping (3SI), with the overall objective of collaborating with Native gardeners to begin a 3SI research and education plot at Iowa State University’s Horticulture Research Station. Our central hypothesis is that working in collaboration with Native people to use their cultural knowledge of 3SI to design current gardening systems will result in improved yields and soil heath. Our rationale is that by working collaboratively with Native gardeners, our research will provide evidence for the socio-cultural, nutritional, and agroecological benefits of rejuvenating Native agriculture. Our specific objectives are to:

    1) Assess the cultural, nutritional, and agricultural importance of 3SI among 5 Native American communities. To accomplish this objective, we will use interviews, community surveys, and evaluations of geographic food availability to explore the impacts of revitalizing the practice.

    2) Engage Native gardeners/farmers through citizen science. To accomplish this objective, we will advance our current collaborations with Native gardeners to collect soil and crop data from their own Three Sisters gardens.

    3) Evaluate the effects of 3SI on crop yield and soil health. To accomplish this objective, we will use citizen science data collected in Objective 2 and establish a collaborative long-term 3SI research and education plot at Iowa State University, designed with direct input from Native gardeners. 

    Learning outcomes will include increased awareness of the cultural, nutritional and agroecological value of 3SI to Native communities.  Native participants will gain deeper knowledge of soil health and the skills to test their soil. Action outcomes include improved agroecological practices for soil health. Participants will take soil tests and implement the soil based on the results.

    Project objectives from proposal:

    Learning outcomes will include:

    1) increased awareness of the practice of 3SI and its historical, cultural, and nutritional value to the community.

    2) deeper knowledge of soil health, the connection to nutrition, and the skills to test their soil.

    Action outcomes will include:

    1) broaden and deepen community engagement with personal and community gardening (via learning outcome 1).

    2) improved agroecological practices that promote soil health through learning outcome

    3). Long term action outcomes of our collaborations include developing improved strategies for 3SI to increase the sustainability of Native communities and greater cooperation among ISU and Native communities and partners.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.