Place plants in your garden next to their friends to improve yields

You might not know it, but plants have friends, too. And some crops fare better when planted next to or near their friends.

Companion planting refers to the establishment of two or more crop species in close proximity so that some cultural benefit is derived. Most often used in home gardens, University of Tennessee Extension commercial vegetable specialist Dr. Annette Wszelaki says the cultural benefits of companion planting can include pest control and increased yield. Wszelaki also directs UT’s organic and sustainable crop production outreach program.

“Interactions between plants can take several forms; they may be either beneficial or detrimental,” said Wszelaki. “For example growing basil and tomatoes together may improve the flavor or yield of tomatoes, but using ryegrasses as a mulch can suppress weeds as well as the growth of neighboring small-seeded crops.” The latter is an example of “allelopathy,” which refers to the release of chemicals by one plant that inhibit the growth of another plant.

Wszelaki adds that plants may also interact with other organisms. “Some plants repel pests. When onions and leeks are grown alongside carrots, they can act as a repellant to the carrot fly. Other plants attract beneficial insects that help manage pest populations or enhance pollination,” she said. “Flowers and perennial plants may provide habitat and food sources to predatory beetles and attract bees and butterflies.”

More information about companion planting is available from your local county UT Extension Office or online in in a fact sheet co-authored by Wszelaki, Trap Crops, Intercropping and Companion Planting,UT Extension publication W235-F, available online at http://utextension.tennessee.edu/publications/Documents/W235-F.pdf

Another useful UT Extension publication is Planning the Vegetable Garden, UT Extension publication SP291-M, online at http://utextension.tennessee.edu/publications/Documents/SP291-M.pdf 

You may also consult the national extension website: http://www.extension.org/ Search the terms“ companion plants” and “vegetable gardens.”

UT Extension provides a gateway to the University of Tennessee as the outreach unit of the Institute of Agriculture. With an office in every Tennessee county, UT Extension delivers educational programs and research-based information to citizens throughout the state. In cooperation with Tennessee State University, UT Extension works with farmers, families, youth and communities to improve lives by addressing problems and issues at the local, state and national levels.