Companion Planting Corn, Beans, And Squash – The Three Sisters

Corn, beans, and squash are the three sisters. The three sisters fit together nutritionally and also are companion plants that benefit each other when planted together.

Corn provides carbs, beans provide protein, and squash provides other vitamins and minerals. Together they provide all the amino acids the body needs.

Companion planting is when two or more plants are planted together because the plants benefit the growth of each other in some way. A common example is planting shade loving plants like lettuce in the shade cast by another plant. The three sisters corn, beans, and squash are another common example and have been companion planted together for thousands of years.

The corn provides a natural pole for the beans to climb. The beans are a nitrogen fixing plant that pull nitrogen from the air and put it into the soil. Beans also give stabilizing support to the corn stalk. The last sister is the squash. The large leaves of the squash plant provide cover for the soil reducing soil temperature, weeds around the plants, and retaining moisture in the soil. The prickly vines of the squash plants also provide a barrier to pests.

To be more specific about nitrogen fixing, there is another player at the party that does this. Symbiotic bacteria to the beans, rhizobial bacteria strains, take up residence in the roots of the beans, forming nodules in the roots, and this bacteria is what fixes the nitrogen into the soil that the plants can use. They are symbiotic because the bacteria needs a host and the nitrogen producing bacteria give off the nitrogen the plant needs.

corn root nodules
Here you can see the root nodules of the benefical nitrogen fixing bacteria.

The three sisters are a very sustainable crop. The nitrogen the beans fix into the soil provides essential nutrition for future crops. The three sisters leave a large amount of organic plant matter at the end of the season that provide the soil with further nutrients and organic matter.

Another pro of the Three Sisters that was especially important in the past is the ease of storing corn and beans and seeds from the squash to last through the winter.

History Of The Three Sisters

The three sisters all were native to mesoamerica (Central Mexico, Central Americas, and some of South America). The first of these plants to be domesticated was squash around 10,000 years ago. Squash was first used to make bowls and for its seeds but was eventually bred to be more edible.

Next was corn around 8,000 years ago that got its start with a grass like plant called teosinte. Teosinte was very different from modern corn. The ears were 2 or 3 inches long with only around 20 kernels on an ear and no husk to protect the kernels. Last was beans around 7,000 years ago, that were eventually bred to have more seed pods with larger seeds.

The switch from hunter gatherer cultures to agricultural ones started around 12,000 years ago. These peoples started to domesticate plants and live a more stationary rather than nomadic lifestyle.

The practice of companion planting corn, beans, and squash spread North to modern day America through the Mexico-America border and made its way further North to the Iroquois Indians around the Great Lakes of North America.

Many Native American cultures grew these three plants but it was the Iroquois who named the system the Three Sisters or Deohako.

Iroquois is actually a French term used to describe a union of six tribes: the Mohawk, Oneida, Onondaga, Cayuga, Seneca, and Tuscarora. Many Native American cultures had their own legends about the three sisters. This story of the Three Sisters was recorded as a Mohawk Legend.

Milpa Farming

Milpa farming has its roots in the start of agriculture in mesoamerica. Milpa translates to “cultivated field” and traditionally it is a cleared field planted for two years and then let go fallow for 8 years.

The milpa had a large role in the community as farmers worked together and the food supply for whole communities rested on the yields of the milpa. Farmers of the milpa would plant up to a dozen crops inlcuding corn (maize), avocados, squash, beans, jicama, amaranth, mucuna, sweet potato, melons, and peppers.

As agriculture spread North some of the tropical plants couldn’t be grown but the corn, beans, and squash were the hardiest of these plants and the most suited to grow in northern climates. They were bred to produce in shorter time and be ready to harvest and store before winter.

The Travels Of The Three Sisters

After Columbus opened up voyages between Europe and the Americas corn, beans, and squash were brought over to Europe and spread to Africa and Asia. At the time the squash family only had 5 or so commonly grown varieties but the number exploded in the next few centuries.

These species were separated by their shape with some being round and some elongated. Squash was especially popular in Italy and Italian American immigrants introduced the zucchini to America in the 1920’s. It took some time for the vegetable to gain popularity but now it is the most economically important squash.

Many bean varieties are also originally from the Americas and then bred into existence on other continents and have now made it round trip and are commonly grown in the Americas again.

Three Sisters Garden Layout

There are several traditional layouts of the three sisters garden and different growing strategies for Native American nations that were in different parts of the country.

The typical layout for northern and eastern nations with plentiful rainfall during the growing season was large mounds 3-4 feet in diameter that were about 4″ high. Four corn plants are planted first in the center in a circle. When the corn reaches 4″ tall four beans are planted in the mound 3″ further out from the corn plants. Once the bean plants have emerged two squash plants are planted on opposite sides of the mound just outside the mound. Mounds were planted in rows with mounds spaced 3-4 feet apart. In the northeast and in areas where fish were plentiful fish carcasses were planted in the mounds for fertilizer.

Another method was to plant plots of each of these vegetables next to each other. So a small field of corn next to a small field of beans next to a small field of squash in a big rectangle. Then they would rotate crops to the right with the corn following the beans so the heavy feeding corn can benefit from the nitrogen fixing of the beans. The squash would be planted 3 feet apart in any direction and the corn and beans 6-12 inches apart in rows that are spaced 18 inches apart.

In arid areas the Hopi and Navajo would plant the three crops in separate fields with wide spacing so that each plant could get enough water. The Hopi indians grew a fourth sister now called Rocky Mountain Bee plant that was used to attract bees to pollinate the squash.

Please comment below with any thoughts, questions, or experiences you have with companion planting the three sisters: corn, beans, and squash.

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