When did the Three Sisters farming system become established in North America?

The Three Sisters farming system—the interplanting of corn, beans, and squash—became established in North America about 1070 CE.1

This agricultural practice, known as milpa in Mesoamerica, spread gradually from its points of domestication in the south to various Native American and First Nations groups across the continent. By planting these crops together, Indigenous farmers created a symbiotic system where the corn provides a trellis for the beans, the beans enrich the soil with nitrogen, and the squash leaves retain soil moisture and suppress weeds.12

While the term "Three Sisters" itself entered written English in 1851, the agricultural tradition has been a vital, life-sustaining practice for many Indigenous nations for nearly a millennium.12