Companion planting is the planting of different crops in proximity (in gardening and agriculture), on the theory that they assist each other in nutrient uptake, pest control

Pest control

Pest control refers to the regulation or management of a species defined as a pest, usually because it is perceived to be detrimental to a person's health, the ecology or the economy.-History:...

, pollination

Pollination

Pollination is the process by which pollen is transferred in plants, thereby enabling fertilisation and sexual reproduction. Pollen grains transport the male gametes to where the female gamete are contained within the carpel; in gymnosperms the pollen is directly applied to the ovule itself...

, and other factors necessary to increasing crop productivity. Companion planting is a form of polyculture

Polyculture

Polyculture is agriculture using multiple crops in the same space, in imitation of the diversity of natural ecosystems, and avoiding large stands of single crops, or monoculture...

.

Companion planting is used by farmers and gardeners in both industrialized and developing countries for many reasons. Many of the modern principles of companion planting were present many centuries ago in cottage garden

Cottage garden

The cottage garden is a distinct style of garden that uses an informal design, traditional materials, dense plantings, and a mixture of ornamental and edible plants. English in origin, the cottage garden depends on grace and charm rather than grandeur and formal structure...

s in England and home gardens in Asia.

For farmers using an integrated pest management

Integrated Pest Management

Integrated pest management is an ecological approach to agricultural pest control that integrates pesticides/herbicides into a management system incorporating a range of practices for economic control of a pest...

 system, increased yield and/or reduction of pesticides is the goal.