Companion planting
Companion planting is the practice of growing different plant species near one another to influence growth, pest pressure, pollination, or space use.
Allelopathy: The chemical influence of one plant on the germination, growth, or survival of another. Some proposed plant pairings depend on chemicals that suppress neighboring plants or weeds.
Three Sisters: An Indigenous American intercropping system combining maize, beans, and squash. The three crops are arranged to share structural, soil, and ground-cover functions.
Plant competition: The struggle among plants for limited resources such as light, water, nutrients, and space. Poorly matched companions can compete more than they help.
Monoculture: The cultivation of a single crop species over a large area or repeated growing cycle. It provides a clear contrast with the species diversity sought in companion planting.
Biological pest control: The use of living organisms to reduce pest populations or their damage. Companion planting can recruit predators and parasitoids that attack crop pests.
Marigold: A flowering plant in the genus Tagetes, widely grown as an ornamental and companion plant. Marigolds are often planted near vegetables, though pest-control claims vary by species and setting.
Nitrogen fixation: The conversion of atmospheric nitrogen into biologically usable compounds by certain microorganisms. Legume companions can host nitrogen-fixing bacteria, though benefits to neighbors are not automatic.
Polyculture: An agricultural system that grows multiple crop species together or in close succession. This broader approach includes companion planting and other forms of crop diversity.
Trap crop: A plant grown to attract pests away from a more valuable crop. This is a targeted planting strategy that draws pests away from the main crop.
Basil: An aromatic culinary herb in the genus Ocimum, commonly grown in gardens and containers. Garden folklore pairs basil with tomatoes, but reliable benefits depend on the claimed outcome.