Companion Planting and the Quiet Science of the Three Sisters
Corn, beans, and squash, a planting system developed over centuries that still outperforms modern monoculture in certain conditions.
I planted the Three Sisters for the first time two summers ago mostly out of curiosity. I'd read about it, corn, beans, and squash grown together in the same mound, a system used by Indigenous farmers across North America for at least a thousand years, and I wanted to see if it actually worked the way people said it did. It did, and then some.
The system is a piece of applied ecology. Each plant plays a role. The corn grows tall and provides a structure for the beans to climb, eliminating the need for stakes or trellises. The beans fix nitrogen from the air into the soil, feeding the corn and squash. The squash spreads low along the ground, its broad leaves shading out weeds and retaining soil moisture. Three problems, support, fertility, weed suppression, solved by the plants themselves, without any inputs.
The nitrogen fixation piece is worth dwelling on. Beans, like all legumes, form a symbiotic relationship with bacteria in the soil, Rhizobium species that colonize the roots and convert atmospheric nitrogen into a form the plant can use. The plant feeds the bacteria carbohydrates; the bacteria feed the plant nitrogen. When the bean plant dies and decomposes, that fixed nitrogen becomes available to neighboring plants. The corn is essentially being fertilized by its companion.
Modern agriculture rediscovered this principle under the name 'intercropping,' and there's now a substantial body of research confirming what Indigenous farmers knew empirically: polycultures, mixed plantings, often outperform monocultures in total yield per unit area, even if the yield of any individual crop is lower. The system is more resilient too. If one crop fails, the others don't necessarily follow.
What strikes me about the Three Sisters is the sophistication of the observation required to develop it. You'd need to notice, over many seasons, that beans grown near corn did better than beans grown alone, and that the corn did better too. You'd need to track soil fertility across years. You'd need to experiment with spacing and timing. This is science, conducted without the formal apparatus of science over generations.
I think about this when people talk about 'traditional' or 'indigenous' knowledge as if it were somehow pre-scientific. The Three Sisters is the product of careful, systematic observation of the natural world, tested against reality over centuries. That's exactly what science is. The methods were different. The rigor wasn't.