Definition - What does Companion Plant mean?
A companion plant is a plant that is purposefully selected and grown in close proximity to other plants, particularly crops, to provide certain benefits. Many plants, when growing in the same area, will compete for resources. However, some plants are mutually beneficial to each other. Companion plants are carefully chosen depending on the needs of the horticulturalist and the desired effect they wish to achieve with the companion plant.
MaximumYield explains Companion Plant
Companion plants can provide many different benefits to other plants. Some companion plants can offer shade, replenish depleted nutrients in the soil, attract beneficial insects or deter garden pests.
One example of utilizing companion plants is by planting corn, beans, and squash in the same area. As the corn grows, beans use the corn stalk for support and replenish nitrogen in the soil that was taken up by the corn. The squash then serves as a natural weed blocker because its large leaves prevent weeds from getting enough sunlight to propagate.
Another example is to plant carrots and onions in alternating rows, which will allow the onions to help deter pests from the carrots.
Crop are not the only type of companion plants. Some flowers, such as marigolds, help to repel insects.
It should be noted that care must be taken when choosing companion plants as some can cause harm to neighboring plants. For example, if tomatoes and chili peppers are planted in close proximity, the chili peppers will draw whiteflies to the tomatoes.