Together, they became known as the "three sisters," and by about 4,000 BC they were claiming top billing in gardens, store rooms, cooking vessels, and even in religious ceremonies (as gifts from the supernatural) throughout the continent.
Here, we explain the mutually beneficial relationship between these plants and how you can plant your own three sisters garden.
(Whether you're starting your first garden or switching to organic, Rodale’s Basic Organic Gardening has all the answers and advice you need—get your copy today!)
How The Three Sisters Help Each Other Out
Planted together, the tall, sturdy corn stalks provide support for the slender climbing bean vines, helping the beans spread their leaves toward the sun; the nitrogen-fixing bacteria associated with the beans' roots pull nitrogen out of the air and share some of it with the hungry corn’s roots; and the huge leaves of the squash vines shade the ground, acting as a living mulch to keep weeds down and conserve moisture for all three crops.
Related: 7 Secrets For A High-Yield Vegetable Garden, Even When You're Tight On Space
Additionally, bean leaves have sharp hairs which trap some insect pests, and the spiny vines and leaves of squash help to deter four-legged animals from venturing into the patch to sample the tempting corn. (Here are 5 totally humane ways to keep deer out of your garden.)
Why They're Better Eaten Together
Early Native Americans found that eating corn, beans, and squash together promoted health. Nutritionists have only recently explained why: They are all rich in vitamins, minerals, complex carbohydrates, essential fatty acids. But most importantly, when eaten together, the corn and the beans contain all essential amino acids in the amounts required to make up a complete protein.
Related: 8 Foods You Should Always Eat Together
How To Plant Your Own Three Sisters Garden
The three sisters are usually planted in “hills,” or small groups of plants, and those groups are spaced some distance from each other, leaving empty space between them where the squash can spread. In climates with regular summer rains, the hills may be shaped into raised mounds (for better drainage in wet soil), or even just level soil spaced 2 ½ to 3 feet apart.
In dry climates, try shaping hills into shallow depressions, so they can better catch and absorb water. (These will need to be spaced 4 to 6 feet apart to allow each plant’s roots to gather water from a larger area.)
Arrange your hills in a block, rather than in a long single row, for better pollination.
For more specific details on traditional three sister designs for different climates, check out this article on Native American traditional gardens, starting about half-way down the page.
Related: 14 Plants You Should Never Grow Side-By-Side
For a traditional three sisters garden, select heirloom varieties of corn, pole beans, and winter squash that are adapted to your climate. A few years ago in my Pennsylvania garden, I planted a three sisters garden featuring impressive 10-foot-tall 'Cherokee Gourdseed' corn (for cornmeal), 'Cherokee Cornfield' pole beans (for dry beans), and Seminole pumpkins—all heirlooms that have been grown for hundreds, if not thousands, of years in the Eastern U.S. However, a combination of sweet corn, tender stringless green beans, and zucchini would work just as well.
When To Plant
Plant the corn seeds first, planting 3 (or more) seeds, spaced about 6 inches apart, in each hill. In areas with regular rain (or irrigation), plant seeds about 1 inch deep; in dry areas seeds may be planted up to 4 inches deep. Knowing when it’s safe to plant tender crops like corn can be challenging, especially as the weather becomes more variable, but your local wild plants can help: Old timers say it’s safe to plant corn when the oak leaves are bigger than squirrels’ ears (which, if I had to guess, are maybe ¾ of an inch long).
Related: Why You Should Always Plant Flowers In Your Vegetable Patch
Plant beans and squash seeds next, a couple of weeks later, when your corn plants are about 6 inches tall. Plant 2 or 3 bean seeds about 6 inches from the base of each corn plant. Plant squash in their own hills about halfway between the hills of corn and beans. Plant 2 or 3 squash seeds, spaced about 6 inches apart, per hill. Use mulch or a hoe to keep the weeds down until the squash vines cover the garden—they will effectively prevent more weeds from starting.