Three Sisters Planting

Three Sisters is a gardening technique that draws on the wisdom of Native Americans, dating back thousands of years. The name is memorable and represents corn, beans, and squash. These three vegetables complement and support one another in various ways as they grow.

Perhaps Three Sisters is the best of companion planting, and it is certainly one of the earliest examples of intercropping. It’s also a popular way to engage children in gardening. The name, the history and customs of Native Americans, and the interrelatedness of how plants can benefit each other are among the many learning points that inspire numerous lessons.

What are the Three Sisters crops

Corn, which grows tall and upright, serves as a trellis for climbing beans.  In turn, the beans add nitrogen to the soil, which benefits the corn. The squash grows around the base of the corn and its large, prickly leaves help shade the soil, suppress weed growth, and are said to help deter animal pests. 

This popular trio also offers differing nutritional attributes that are important to the diet. Each contains vitamins, minerals, and fiber. Corn is high in carbohydrates. Beans are rich in protein. Squash is a good source of beta-carotene. 

How to plant Three Sisters

Step 1: Select your site.

Corn, beans, and squash are warm-season plants. They thrive in warm summers. Select a site that receives 6 to 8 hours of direct sun daily.

Step 2: Prepare your soil. 

Work the soil in your garden beds so that it is loose and friable. It also needs to be well-drained. Vegetables do best in slightly acidic soils, pH 5.8 to 6.5. A soil test (kits are available from county Extension centers) will give results and recommendations. If you haven’t had your soil tested recently, it may be helpful to do so. Amend your soil with well-composted organic matter to enrich it and allow for better drainage.

Step 3: Decide on the size and configuration of your garden.

Some people grow Three Sisters as a novelty or as a children’s activity. If you are growing to feed your family, general guidelines for a family of four are to grow at least 15 corn plants, three pole beans, and four squash plants. Of course, this varies depending on each family’s taste preferences. 

Remember to site Three Sisters where the corn will not shade other garden plants from necessary sun. Cornell Extension recommends mounding the soil about 12 inches high and between 18 inches and 3 feet in diameter. For dry areas, flatten the top of the mound and make a shallow depression to keep water from running off. 

Arkansas Extension shares that this is a great configuration for growing dry corn and dry beans. If, however, you are growing sweet corn and snap beans, which will be ready to harvest before the squash, you may want an alternative so you aren’t stepping on squash leaves and vines to harvest the beans and corn. An alternative is to plant rows of corn with beans planted in between, and plant squash along one side. 

Step 4: Plant after frost date.

The best time to plant is after danger of frost has passed and when the soil warms up, typically a couple of weeks after the last frost date. Its best to start with corn. 

Step 5: Plant corn first.

While you can plant any sweet corn variety that grows well in your region, Cornell Extension shares that dent, flint, or flour corns are best suited to this system. For a mound that is about 3 feet in diameter, you will need about seven corn seeds. Soak the seeds for three to five hours before planting. Plant them about 1 inch deep and 6 inches apart in the center of the mound. Allow the corn to grow about 6 to 10 inches tall before planting the beans and squash. As the corn grows, thin out the weakest of the seedlings, leaving three or four. 

Step 6: Plant beans.

The best beans to grow for this method are pole beans, which means they will climb the corn stalks. Bush beans may be great options for the garden but not for Three Sisters. Cornell recommends soaking and then planting six bean seeds, about an inch deep in a circle about 6 inches away from the corn. As they grow, thin to the healthiest three or four seedlings. 

Step 7: Plant squash.

After you plant the beans, plant four squash seeds 1 inch deep and about 12 inches away from the beans. This can be done at the same time you plant the beans or a week or two later. As the squash grows, thin to one or two healthiest seedlings. Most summer or winter squash varieties that grow well in your region will work. Avoid any that climb because the corn stalk may not be strong enough to support heavy fruits.

Step 8: Fertilize your plants.

Corn is a heavy feeder, which means it likely will need more nitrogen than the beans can provide. Cornell recommends sidedressing it when it is about knee-high and again when silks appear on the husks. To sidedress with fertilizer, apply aged manure, fish emulsion, or a commercial fertilizer to the soil surface around each plant. Follow label directions and water thoroughly after application.

Step 9: Keep your garden watered.

Your garden will need about an inch of water per week. Presoaked seeds may dry out more quickly and need more water initially.

Step 10: Harvest.

Harvest each crop as it ripens and enjoy!