What is the Three Sisters method of planting?
The Three Sisters is a companion planting method developed by Native American tribes. It involves planting corn, beans and squash together for mutual benefit. Beans are nitrogen-fixing plants, with rhizobia in their roots which take nitrogen from the air and convert it into a form that can be absorbed by the roots of other plants.
Corn provides stalks for the beans to climb. Squash plants cover the ground, thus helping to retain moisture in the soil and prevent the growth of weeds.
The plants grow together symbiotically to deter weeds and pests, enrich the soil and support each other. This method introduced biodiversity, which is essential in attracting pollinators and making the land richer.
A brief history of the Three Sisters
The method originated from the Iroquois tribe that occupied the regions around the Great Lakes in Northern US and Canada. When the European arrived in the Americas in the early 1600s, they had been using this method for over 300 years.
The plants were also planted together for their nutritional value. Corn is carbohydrate-rich and thus provides energy, beans are rich in protein and squash contains vitamins that supplement their diet.
The companion plants in the Three Sisters are:
You should plant tall varieties to give beans room to climb. Shorter species of corn will not work well because they might be overcrowded by the beans. You can plant dent corn, sweet corn or popcorn in your farm.
Climbing types are preferred over bush types. Yardlong, Blue Lake, common beans, runner and lima are best for the Three Sisters method. You should ensure to inoculate your seeds with Rhizobium bacteria to enhance nitrogen fixation. Plant beans when corn is about knee-high, to facilitate better support in the early stages of germination.
It is best to plant summer varieties or a combination of both winter and summer. Zucchini is a summer squash that grows bushy, stays small and remains upright. They can work well in a raised bed. Ideally, the vines on your squash should spread a few feet in order to cover the soil adequately.
Avoid winter varieties such as Pink Banana which can spread over 15ft, potentially overwhelming the other two Sisters, especially if you have a small garden. You should plant squash with vines that spread from between 4 to 8ft.
In some cases, a Fourth sister can be incorporated, typically Sunflower or Aramanth. They offer shade, provide more climbing stalks and attract pollinators.
See this guide on different combinations of plants that grow well together.
Does Three Sisters planting really work?
The practice has been perfected for hundreds of years and its nutritional and biodiversity value is well documented. Researchers in the early 20th century acknowledged the benefits of the Three Sisters to the Iroquois tribe. Planting the three crops together took less time and effort compared to planting them individually in different sections of your land.
The Three Sisters system has been found to enhance the physical and biochemical environment of the soil, reduce soil erosion, manage plant population and spacing, control weeds and provide nutrients in the right quantities. Further, the Three Sisters is better than monoculture cropping due to its high energy yield. A scientific study conducted on the Three Sisters revealed that it supported more people per hectare as compared to monocultures of individual crops.
Three Sisters planting layout and spacing
Three Sister mounds
- This is the common way for planting used by the Iroquois.
- Involves planting in mounds to prevent rotting.
- The soil mounds should be 4 inches high, with a small crater in the center.
- For corn, plant 4 seeds in the crater, 6 inches apart, 1-3 inches deep.
- Once corn gets to a height of 4 inches, plant 4 bean seeds on the sides of the mound, approximately 3 inches from the corn plant, 1 inch deep.
- When the bean emerges, plant 2 squash seeds 24 inches from the center of the mound on each side.
- Train the vines away from the mound to prevent crowding the corn and beans.
- You should create access paths between the mounds to allow for easy harvesting.
The Three Sister field
- Ideal for corn pollination as it is planted in a large block.
- On a square piece of land, plant beans along the outer edges and corn in the center. Plant squash on one edge of the land.
- Plant corn 1-3 inches deep, 6-12 inches apart.
- Plant beans 1-inch-deep, and close enough to climb the corn, approximately 3-12 inches away.
- Plant the squash row 3ft away from the row of beans. Plant 2-3 seeds at each place, 3ft apart. Isolate the squash to one side of your square field to make it easier to access the beans and corn.
Three Sister landscape
- Concentrate corn, beans and quash in different areas of your field.
- Shift the crops to the right each year.
- Follow beans with corn as they will have fixed nitrogen in the soil.
- Plant corn and bean seeds 6-12 inches apart in rows 18 inches apart.
- Plant squash in rows 3ft apart.
There are different variations for garden layout in Three Sisters planting, with the main consideration being space constraints. You should give individual plants enough space to thrive and ensure you have enough of each type of crop to ensure efficient pollination.
Beans are self-pollinating, so you can plant a few seeds in your garden. Squash is insect-pollinated so you should have more in order to attract pollinators. Corn is wind-pollinated so it is best to plant at least 10-20 heads to increase the likelihood of success.
How to plant Three Sisters in a small garden
- You should plant the sisters in clusters on low mounds.
- Choose a sunny location that receives at least 6 full hours of sunlight.
- Each mound is about 4ft wide, with 4-6 corn plants.
- Prepare the soil in the spring with organic matter and weed-free compost.
- Prepare your mounds and space them about 4ft.
- Plant the corn first, typically after the frost has passed.
- Plant beans when the corn stalks are strong enough to support them, ideally at 6 inches tall. Four beans should be evenly spaced around each stalk.
- After around a week, plant squash seeds around the mound. Put two seeds in each hole, to increase the chances of germination.
What is squash used for in a Three Sisters garden?
Squash shades the ground, helping to preserve moisture in the soil and choke out any sprouting weeds. The vines are a deterrent to pests because they are covered in prickly hairs.
The Three Sisters method was widely practiced by Native American tribes. You plant three crops, squash, corn and beans, which symbiotically benefit each other. Corn provides tall stalks for climbing beans. The beans fix atmospheric nitrogen to enrich the soil. Squash helps to conserve water in the soil and prevent weeds.
The Three Sisters provide sustainable soil fertility and a nutritious diet. You can adopt different layouts for your garden, and you will enjoy the full benefits of this ancient farming practice.