Companion planting

Companion planting is one of the fundamentals of permaculture and organic farming. It is the practice of placing different crops in close proximity of each other, so they will be mutually beneficial.
One of the earliest examples of companion planting we have today is that of the Native American peoples, who planted corn and pole beans together. The cornstalk would become a trellis for the beans to climb up. With the addition of squash, they pioneered what became the Three Sisters technique.
Plants are chosen as companion plants for the functions that they can provide, which can be grouped into the following categories: dynamic accumulators, edible nitrogen fixing species, green manures, weed inhibiting plants, weed barrier plants. Companion plants may also serve to attract beneficial wildlife or provide physical support or protection.
Companion planting was widely touted in the 1970s as part of the organic gardening movement. It was encouraged not for pragmatic reasons like trellising, but rather with the idea that different species of plant may thrive more when close together.
The combinations of plants also make for a more varied, attractive vegetable garden. Many of the modern principles of companion planting were present many centuries ago in the cottage garden.
==Examples==
===Pest-repelling and pest-luring companions===
Nasturtiums are well-known to attract caterpillars, so planting them alongside or around vegetables such as lettuce or cabbage will protect those crops, as the egg-laying insects will tend to prefer the nasturtium.
Crops that suffer from greenfly and other aphids may benefit from the proximity of marigolds: these attract hoverflies, a predator of aphids, and are also said to deter other pests.
===Companions that attract and nurture beneficial animals===
Another form of companion planting involves the use of plants that produce copious nectar and protein-rich pollen or that provide shelter for beneficial wildlife species (typically insects). 
Nectar- and pollen-rich plants in a vegetable garden provide abundant food for pollinators, and plants such as milkweed offer a location for Monarch butterflies (a pollinating species) to lay their eggs. Some insects in the adult form are nectar or pollen feeders, while in the larval form they are voracious predators of pest insects, providing different benefits at multiple life stages. 
==See also==
Intercropping, Monoculture, Nurse crop, Three Sisters
==External links==
* A companion planting table
* Companion Planting How the Iroquois employed companion planting principles.
* PlantBuddies – Interactive tool for companion plants (open source)
Category:Organic gardening
Category:Techniques
Category:Companion planting
Category:Plants