How does the Three Sisters farming system combine corn, beans, and squash?

The Three Sisters is a traditional Indigenous agricultural system—also known as milpa—that utilizes intercropping to grow corn, beans, and squash together in mounds or hills. This symbiotic relationship relies on the unique growth habits of each plant:12

• Corn: As the eldest sister, corn emerges first and provides a natural, sturdy trellis for the beans to climb.12
• Beans: These plants climb the cornstalks and enrich the soil by using nitrogen-fixing bacteria in their roots to provide natural fertilizer for the other crops.12
• Squash: The youngest sister grows along the ground, where its large, fan-shaped leaves shade the soil, helping to retain moisture and suppress weeds.12

This method creates a resilient, biodiverse ecosystem that is less taxing on the soil than monocultures and provides a balanced, nutritious diet of starches, proteins, and fats.1