All healthy ecosystems contain a complex system of microbes, insects, plants, and animals that interact to maintain balance and contribute to the well-being of a given space. Companion planting is a targeted effort to exploit the benefits of the relationships between specific plants to improve production vitality. More simply, companion planting is a specific type of polyculture [i.e. growing multiple species of plants in the same space], where two plant species are grown together because it is known or theorized that they synergistically improve each plant’s growth.
Improving plant growth can be the result of a variety of process. For example, the natural substances produced by plant roots and flowers may attract beneficial insects which may pollinate crops or consume pests. Planting multiple crops in the same space may also deter pests that either find the scent of the companion crop to be off-putting or because the companion crop works like a scent barrier.
There is also evidence that certain plant relationships can augment plant growth by improving soil conditions [e.g. when nitrogen-producing legumes are used], support disease resistance, and enhance crop flavor.
In any case, successful companion planting requires an understanding of the functionality of the selected plant species. In an ideal situation, both the companion plant and the target crop will be harvestable to provide an economic benefit to the farmer. However, this is not always the case. In such a situation, the economic benefits from an improved yield of should outweigh the cost of a ‘sacrificial’ companion crop.
At present, there is limited institutional research on companion planting, albeit the body is growing. Instead, there is a great deal of ‘folk’ knowledge that is rooted in local traditions and practices. Unfortunately, much of this expertise has been lost due to the industrialization of agriculture which favors mechanical and chemical production methods. However, as the sustainability of these practices is questioned, demand for more traditional and holistic production methods is growing which will likely prompt further inquiry into the benefits of companion planting.
- Bomford, M. K. (2009). Do tomatoes love basil but hate Brussels sprouts? Competition and land-use efficiency of popularly recommended and discouraged crop mixtures in biointensive agriculture systems. Journal of sustainable agriculture, 33(4), 396-417.
- Last, R. (2016). Plant Guilds: Taking Companion Planting to the Next Level. Unpublished. https://doi.org/10.13140/rg.2.1.4310.6805
- Parker, J. E., Snyder, W. E., Hamilton, G. C., & Rodriguez‐Saona, C. (2013). Companion planting and insect pest control. In Weed and Pest Control-Conventional and New Challenges. InTech.
- Riotte, L. (1998). Carrots love tomatoes: secrets of companion planting for successful gardening. Storey Publishing.