Although native peoples from different parts of North America used a wide range of agricultural techniques, perhaps the best known is the interplanting of corn, beans, and squash together -- a trio considered by the Iroquois Indians of the east as "The Three Sister."
Although not widely used in the U.S. today, interplanting of the three sisters is a well-conceived planting system in which different crops benefit one another. Many stories, customs, myths, and legends are associated with the three sisters, which have played such an important part in Indian agriculture and nutrition. Together, the crops gave strength and life to each other and nourished the people.
The corn supports the beans as they grow upward. The beans can convert nitrogen from the air into a form that plants can use. The nitrogen remaining after the beans have grown will be available for the corn, which requires a good deal of nitrogen, the following year. The squash covers the soil, helping to control weeds and deter predators such as raccoons who love to feed on corn. And the sisters complement each other nutritionally as well, with the corn supplying carbohydrates, beans giving protein and some extra vitamins, and squash contributing vitamin A.
Growing your own three sisters garden or planting the crops in a small patch outside your home or school can provide a springboard for tying in studies of Native American customs, nutrition, and folklore, as well as investigating plant growth and relationships. To plant a typical three sisters system, make slightly raised areas (hills) about 12 inches high and 18 inches in diameter three- to four-feet apart in all directions. In each hill, plant half a dozen soaked corn seeds in a small circle. (Note: popcorn doesn't usually grow tall enough for this system and may get overwhelmed by the beans." As corn plants begin to grow, weed gently, mounding up soil around the plants. When the corn is about six inches high, plant four to six seeds of pole beans around the circle. Then plant four or five pumpkin or squash seeds either in every seventh hill, or plant a couple of seeds if you have just one hill. If you plant too many, they'll overwhelm the other crops.
Be sure to pay attention to watering and fertilizing your three sisters planting. The Native Americans and early settlers, it's said, often buried a dead fish in each hill which, as it decomposed, provided nitrogen and other nutrients for the plants. Perhaps your students will want to experiment to see how well this fertilizing method works.
To enrich a three sisters planting project, consider researching some of the folklore and customs surrounding planting these crops. For instance, the Iroquois planted the seeds "with kind thoughts three days before the full moon." Garden consultant Judy Isacoff Thomas had students in Castleton, NY, create and use "magic planting sticks" from felled trees, decorated with yarn, cornhusks, and feathers.
"We had talked about the three sisters, but didn't have the room outdoors to plant them," reports fourth grade teacher Wendy Maynard, in Daly City, CA. "So students suggested trying to grow them right in the GrowLab." Using a large pot, the students figured out that based on planting distances, they could only plant one corn plant, two bean plants, and one squash plant.
Although they never expected to grow these crops to maturity indoors, they were able to see the pole beans twine around the corn, the squash forming a lower mat, and began to get a sense of how the three sisters grew together.