Take your gardening skills to the next level and let nature do the work. We lift the lid on the Three Sisters gardening method.
Looking at the way that produce grows in farms and gardens, one might think that each type of vegetable must grow alone. Separate growing spaces are often filled with one variety; a cornfield, for example, is hardly a place you would expect to find beans. However, before humans cultivated the land, plants needed to work together to flourish. Many ancient civilisations saw the relationships between certain plants and the benefits they brought, leading them to cultivate these plants together in the belief that they would grow better.
What is companion planting?
Although companion planting is often overlooked in favour of single-species cultivation, many people are now rediscovering its benefits, such as pest control and weed prevention. Take, for example, marigolds, or Tagetes. Many people enjoy marigolds for their bright blooms and ease of growing – but for companion planters, these flowers are especially helpful and are often grown alongside tomatoes. Marigolds release compounds into the soil that can kill and repel parasites like nematodes, protecting nearby plants. They also release limonene, which deters many pests, from whitefly to cats! If that weren't enough, they attract beneficial pollinators, like bees and wasps, who can pollinate nearby tomatoes and prey on pests such as aphids. Some use them as sacrificial plants – snails and slugs enjoy marigolds, so planting them as a barrier means these slimy creatures are less likely to destroy the nearby tomatoes.
As you can see from this example, companion planting has many benefits. Given that many gardeners and farmers want to reduce their reliance on chemical pesticides and weedkillers, allowing nature to help with some of those jobs can save time, money, and resources.
What is the Three Sisters gardening method?
The Three Sisters is a great method for beginners’ companion planting. It comes from traditional Native American societies that saw how the talents of each plant helped the others. The three sisters themselves are corn, beans, and squash. Not only do these vegetables grow well together, but they also provide a fairly nutritionally complete diet; eaten together, the amino acids of each plant form complete proteins that would otherwise need to be found in meat. The corn provides starchy carbohydrates, beans are high in protein, and squash is replete with vitamins. Yes, variety is the spice of life, but if you want to grow your food and you’re short on space, you could do a lot worse than these three plants.
Corn, beans, and squash don’t look like sisters, but they do act like them. The eldest sister of the three is corn. Corn shoots up to care for her younger sisters; the tall stem supports the middle sister, the bean, and the placement of the leaves allows room for the others to absorb light.
While the bean climbs upwards, its true talents are found underground. Beans absorb nitrogen from the atmosphere and feed it to Rhizobium bacteria in the soil, which then fixes the nitrogen into the earth, benefiting the plants. Corn, in particular, thrives on nitrogen-rich soil.
As the youngest sister, the squash is the last to rise - and she doesn’t rise far. The squash leaves create a carpet that soaks up the light that makes its way through the taller plants. This carpet makes it harder for weeds to grow, benefiting the other plants.
Between them, the Three Sisters provide support, nitrogen, and weed suppression, allowing them to flourish together. As a result, those who use the Three Sisters system find that they have to do less work and manage fewer resources; weeds are prevented by the squash, nitrogen-rich soil is provided by the beans, and the corn works as a beanpole!
How to Grow a Three Sisters Garden
The Three Sisters system is a beginner-friendly way to start companion planting. To begin, you will need a few things:
- Corn seeds
- Bean seeds
- Squash seeds (preferably winter squashes or pumpkins, but most varieties will work)
- Sunflower seeds (optional)
- A raised bed or other clear space for planting – ideally, you will need at least 3 square metres, but smaller spaces can work in a pinch. Just remember that you will need at least 10 corn plants to ensure proper pollination
The first step is to plant your corn. You can plant your seeds directly into mounds of soil, with about 45cm between them, or you can sow them into modular trays and plant them out when the seedlings are large enough to handle. You won’t add the other plants until these have grown a bit, as the corn needs a head start to support the beans.
When your corn is about 30cm tall, it’s time to add the beans and squash. French beans are great for this system, as are green beans. You will need to plant your beans about 5cm away from the corn – again, you can either plant them into the ground or plant them in cells and transfer them when they are large enough to handle.
For the squash, you will need a vining variety; think pumpkins, butternut, or spaghetti squash. If you’re not a squash fan, you could replace this with other cucurbits, like watermelons or courgettes. Squash needs a lot of light; hence, these plants will sit about 60cm from the middle of the mound. Remember that they will spread out and take up quite a lot of room once they are established.
How to improve your Three Sisters garden
While these plants work well together, they might need a little help to get started. Corn requires a lot of nitrogen to grow, and while your Three Sisters patch will retain the beans’ nitrogen year after year, you might want to add some nitrogen-rich soil before planting your corn for the first time to speed up the process. Similarly, while the squash leaves will spread and prevent weeds, you should still pull weeds until the squash is established.
Some gardeners add a fourth plant to their Three Sisters garden: the sunflower. This is completely optional but does provide some benefits. For example, as a tall plant, the sunflower can also support the beans. It can also attract pollinators, and its seed head can be used sacrificially to distract birds from your maturing corn. Plus, at the end of it, you will have sunflower seeds, which make an excellent snack or garnish when roasted! While the sunflower is not an integral part of the Three Sisters, she could be viewed as a helpful family friend.
Once you have grown a successful Three Sisters garden, you will probably be struck by the ways in which different plants can help each other flourish. We would love to see your companion gardens – tag us on Instagram @agroyemedia to show off your hard work!
Megan Diehl is a dedicated writer who loves to explore the world of food and agriculture, sharing insights that connect people to the roots of their sustenance. When she isn't writing, Megan can usually be found cooking for her family, creating textile art and gardening.
