Companion planting is a horticultural practice which involves planting two or more plant species together, usually with the goal of creating a mutually beneficial situation for both, or with the idea of promoting better growing conditions for a cash crop. Numerous examples of companion planting can be seen throughout history, including the notable “three sisters” of the Americas: beans, corn, and squash. This gardening technique is used by some organic gardeners who wish to grow a healthy garden naturally, and some larger farming concerns also utilize companion planting to increase crop efficiency and yields.
A number of different goals can be accomplished with companion planting. For example, a gardener might use companion planting to create a trap crop which draws insects, slugs, and other pests away from a more desirable cash crop. Nasturtiums, for instance, are very popular with moths and slugs, and since they have minimal commercial value, they make a great trap crop for things like cabbages and leafy greens. In a related concept, nurse plants are commonly used in companion planting to protect tender young plants in the early stages of growth; nurse crops protect plans from sun and wind damage as well as potential pests.
Companion planting can also be used to naturally control insect pests. Flowers like marigolds are offensive to insects, so they can be utilized to repel insect pests which could damage a crop. The converse is also true, with flowers which are attractive to pollinators like bees and butterflies being used in orchards to encourage pollination of nuts and tree fruits. Plants hostile to humans and large wildlife, such as thorny shrubs, may be planted as a natural fence to protect tender crops from marauders.
Flavor enhancement can also be accomplished with companion planting. Some plants taste better when grown with certain herbs, and companion planting can also do things like lower the sulfur level in onions, making them sweeter and more palatable. Nitrogen fixers like legumes are often used in companion planting to enhance the condition of the soil for other plants, and climbing plants are often used to provide shade for young plants, while tall crops such as corn are used as trellises for climbers like beans.
When gardeners utilize companion planting, they may refer to it as “polyculture,” because they are growing multiple crops at once. Numerous guides to polyculture can be found in garden supply stores, including lists of recommended companion plants as well as incompatible companion plants which should be avoided. People who are just starting to experiment with companion planting may want to start small and see how it works out before expanding into the entire garden.