Companion planting is the methodology of growing certain plants together in order to increase yield, reduce pest infestations and allow one plant’s characteristics to benefit others. The idea of planting certain plants together has been practiced by farmers around the world since the development of early agriculture, around 8,000 BC. Through trial and error, farmers discovered that some plants flourished next to others, while alone they languished. These traditions were passed down from generation to generation, applied by farmers hoping to avoid unnecessary crop failure due to pests, drought and disease while at the same time increasing crop production. Although these primitive farmers may not have understood the science behind why certain combinations worked, inevitably different cultures around the world developed their own sets of winning companion plants that improved the chances of success.
There are a few extremely well known examples of companion gardening which have been well proven even in modern times, to increase yield and mutual plant protections. One of the most famous combinations is the holy trio of corn, squash and beans grown in eastern and southern North America before the arrival of Columbus. Corn is nitrogen hungry, so growing beans alongside corn restores nitrogen levels to the soil. Bean stalks use the corn stalks as a support for their runners to better reach the sun’s rays, and squash both protected the soil from drying out, while protecting the corn from being ravaged by critters. If ever there were three plants meant to grow in unison, it is this famous trio. They represent one of the best examples of how well companion planting can work.
Shockingly, due to the monoculture farming practices of the past century, companion planting is becoming a long-forgotten practice. Industrial farms these days rely on fertilizers to replace lost nitrogen, or pesticides to reduce insects. Instead of being influenced by industrial farming techniques, it’s much easier, safer and healthier to make use of companion gardening to boost yields. Why fill your garden, and subsequently your body, with chemicals when a little bit of age-old garden lore will actually do the trick?
There are some plants in your garden, which are notoriously susceptible to pest infestation, some of these are peppers, tomatoes and potatoes. Instead of resorting to insecticide, why not find out which companion plants could lure the bugs away, or even better, offer a natural protection?
Tomatoes: The combination of tomato and asparagus has benefits going both ways. Tomatoes are targeted by pesky nematodes that can be easily fended off when tomatoes are interplanted with asparagus. Asparagus on the other hand can be infested by the asparagus beetle, which are thankfully repelled by the tomato. Talk about some vegetables working together!
Nasturtiums: A flower that is both beautiful and edible, great for repelling nasty aphids, potato bugs, and other nasty critters that target squash, pumpkin and beans. An excellent addition to any greenhouse, as it also protects against whiteflies.
The most visible benefit of companion gardening is seeing how cover crops protect against drought, or how taller plants can shade sensitive plants. Planting crops together to protect them from the harsh elements is a time-tested method and one of the easiest ways to understand the theory of companion gardening.
Corn: Corn is a great crop to use to protect shade loving plants, like lettuces, who can often burn up when planted during the high heat of summer. As the corn ripens, and dries out, it will allow the gentler fall sun to nourish the remaining lettuces into the autumn months. Having a ground cover will also protect the soil from drying out around the corn.
Pumpkin & Squash: These plants offer excellent ground cover throughout the hot summer months. They prevent weeds from making their way through, reduce moisture evaporation, and when grown alongside corn can prevent raccoons from stealing your crop!
Increased Yield & Flavor
There are certain combinations that seem to work in more mysterious ways, beyond simple observable benefits like offering shade, or insect repellents. Although these more nuanced benefits are well proven, the scientific reasoning is still unclear. These benefits, which are more difficult to observe and measure, are the ability to increase yield and flavor through companion planting.
Basil: When planted next to tomatoes, basil has been shown to enhance flavor and strengthen the tomato against seasonal hardships. This may also be the case when planted next to peppers.
Onions: Although it is a great way to deter many pests, especially maggots, if planted next to chamomile or summer savory, the flavor of the onion can also be improved.
Calendula: An excellent herb, it is a great way to attack pollinators throughout the growing season to increase yield and garden performance for nearly all flowering garden fruits.
Words of Warning…
Just as there are plants that work extremely well together, there are also many plants that can have disastrous effects if planted side by side. It’s a good idea to do a bit of research before planting your garden in order to determine if you really should put your potatoes next to your cucumbers (hint, you likely shouldn’t because the cucumbers will encourage potato blight!). Other well-known vegetable enemies are listed below.
Fennel: Harmful to the growth of nearly every other garden plant, keep it separate!
Chervil: Can attract slugs and parasitic wasps, so keep it away.
Kohlrabi: Known to stunt tomatoes