Winter squash, maize, and climbing beans planted in close proximity as 'companions' ensure bountiful harvests.
Three sisters agriculture is an ancient planting technique used by Native Americans. It is a companion planting method for growing the three main vegetables that form their staple diet: corn, winter squash, and pole beans. In Haudenosaunee society, the three sisters crops were usually grown by women outside the defensive walls of the village. In this system the roots of the bean plants produce nitrogen to fertilize the soil, while corn stalks provide a natural structure for the beans to climb. The dense winter squash leaves retain moisture in the soil, saving water, while also providing protection in stormy weather. The prickly stalks of the squash plants also prevent crop damage from herbivores. Lastly, the three plants constitute a healthy balanced diet.