Permaculture is just now rediscovering the style of garden that fed North America for thousands of years. Native peoples grew all of their staple foods without either draft animals or mechanized equipment. Far from being a drudgery, Native American gardening was much less labor-intensive than the type of gardening we know now. It was based on plants that came from the Americas and love to grow here--corn beans, and squash. These main crops were called "the three sisters." Because the sister crops were the staff of life, they were the focus of legends, songs, and ceremony.
The sister crops work in home gardens today for the same reasons they worked for First Nations farmers: They produce big yields without mechanized equipment:
From time to time, articles appear about three sisters gardens. But they usually don't tell several important things that this sheet hopes to cover:
Corn is the basis--the older sister. You plant the corn first, and it forms a tall trellis for the beans to grow on. It's deep roots break up the soil for the weaker bean roots. And the sugars in the sap of the corn plant leak out an to the soil a little bit, giving other plants--as well as soil microorganisms--energy to grow with. In three sisters planting, you need a tall, sturdy corn that can handle the weight of the pole beans. To prevent lodging,(falling over) it is a good idea to plant the seed fairly deep (1”) and to hill up soil around the base of the little corn plants before you plant the beans. Planting in clusters helps with stability as well.
Beans are next—the giving sister. Planted after the corn is a foot high, they climb up the corn, so you can grow high-yielding pole beans without constructing a trellis. Beans have nitrogen-fixing bacteria on their roots, which keep the hungry corn from depleting the soil nutrients. Transpiration of moisture from the corn leaves allows the bean vines to be in full sun without so much heat stress. The beans are planted after the corn is 8” high, one bean per stalk.
Squash—the protecting sister--provides the living mulch that conserves moisture and keeps the sun from baking the soil. It's tangly, prickly vines and leaves make it harder for marauders (like raccoons) to get to the corn. The squash is planted 2-3 ft from the corn, since it is big & vigorous.
Sometimes there is a fourth sister. In fertile areas like the Midwest, it would be the sunflower. (You can grow beans up sunflowers as well.) In drier areas, basketry or ceremonial plants were added. I like a few zinnias at the edges. They contribute by drawing beneficial insects that eat pests. I have also added radishes under the squash leaves, where they stay cool and shaded. Their brassica scent seems to keep squash bugs from finding my squash plants so quickly. The key to adding other plants is that they need to fill a different niche and have a unique contribution to the whole.