Companion Planting: For Happier Plants, Grow a Garden of Good Neighbors

Companion Planting: For Happier Plants, Grow a Garden of Good Neighbors
Nasturtiums are remarkably good at deterring aphids from neighboring plants such as beans. (andre quinou/Shutterstock)
6/1/2022
Updated:
6/2/2022
0:00

You know that friend that you just feel right with? You may not see them for weeks, months, or even years, but when you meet up, it’s as if you saw them just the day before. You go together like peaches and cream, tea and scones (that’s a British thing), or peanut butter and jelly (definitely American!). You compliment each other’s existences. You just fit.

Plants have such friends. To be honest, sometimes the friendship isn’t entirely altruistic and one may come out a little worse for wear from the relationship, but plants are decent souls. They don’t complain, get into shouting matches, or fight. They take it on the chin like the troopers they are.

Take the humble nasturtium. In addition to having beautiful, edible flowers and delicious, peppery leaves, it’s also remarkably good at deterring aphids from plants such as beans. Unfortunately for the nasturtiums, this is a case of “taking one for the team,” as simply put, aphids love them. The poor nasturtium is a living sacrifice.

The centuries-old “three sisters” method of companion planting is a prime example of a mutually beneficial friendship—plants being perfectly comfortable in each other’s presence. Corn, runner beans, and squash are grown together. The corn provides support for the beans; the beans (the most caring of the sisters) produce nutrients, as members of the legume family fix nitrogen into the soil; and the squash provides ground cover, thus reducing weeds and evaporation.

Before planting your garden, consider which plants would make good neighbors. (Greta Hoffman/Pexels)
Before planting your garden, consider which plants would make good neighbors. (Greta Hoffman/Pexels)

Support System

A huge proportion of the plants we eat today are grown in vast monocultures—swathes of single-species crops as far as the eye can see. This form of farming potentially leaves these crops open to suffering from the same diseases or attacks by pests that are particularly fond of that plant. Monoculture farming isn’t great for the natural environment, either. It gives next to nothing in terms of enhancing biodiversity and does little to improve soil quality; after all, each plant in a monoculture needs the same nutrients.

Companion planting is a form of polyculture. Different species are grown in close proximity to each other, each having different nutritional requirements and root structures and each offering something different to the surrounding ecosystem. This may be aiding pollination through the attraction of insects or keeping pest numbers down by repelling them.

When choosing which plants should be planted next to each other, several factors should be considered, including the size and shape of each plant, if it’s greedy for certain nutrients, whether it produces nutrients that can be shared, what it attracts, and what it repels. Plants need to be made comfortable in order to thrive. Imagine boarding a long-haul flight only to find yourself seated next to a person who ever-so-slightly overlaps your seat and is wearing cheap aftershave. Personally, I’ve been encroached upon by a neighboring “potato” on many a flight. Let’s not let our plants suffer in a similar way!

Herbs such as basil, sage, rosemary, and thyme are also excellent at repelling pests as well as being delicious in their own right. (Irina Fischer/Shutterstock)
Herbs such as basil, sage, rosemary, and thyme are also excellent at repelling pests as well as being delicious in their own right. (Irina Fischer/Shutterstock)

What to Consider

If we take food production back to how it used to be, when people ate more seasonal foods in smaller quantities and biodiversity was greater, we can benefit ourselves and the surrounding environment—all starting from our own backyard gardens.

In order to maximize crop production per square foot, an important consideration, especially if you have a small garden, is that fast-growing plants can be grown between slower-growing species and picked before the latter have matured.

Many plants are strongly scented. If used in companion planting, these scents have the potential to confuse pests who locate their host plants by their aroma.

Lavender is a favorite of bees, butterflies, and hoverflies, which will pollinate your veggies. (Peter Turner Photography/Shutterstock)
Lavender is a favorite of bees, butterflies, and hoverflies, which will pollinate your veggies. (Peter Turner Photography/Shutterstock)

Anyone who has grown carrots will no doubt have felt the disappointment of pulling up a long-awaited root only to find it full of holes and carrot root fly larvae. Cue the cheap aftershave! If plants such as alliums (garlic, onions, scallions, shallots, leeks, or chives) are grown next door to them, their powerful smell will ward off the carrot root flies. Likewise, the smell of carrots can deter pests from leeks and onions. Isn’t nature clever?

Mint is particularly good at preventing attacks from pests, as its aromatic scent can mask that of the surrounding plants. It can also be used as an effective companion for tomatoes and members of the brassica family. Do take care with mint, however, as it will quickly overtake your garden—which is fine if you have an unhealthy relationship with mojitos, but not if you want to maintain garden space for other plants!

The "three sisters"—corn, beans, and squash—have been planted together for centuries. (JoannaTkaczuk/Shutterstock)
The "three sisters"—corn, beans, and squash—have been planted together for centuries. (JoannaTkaczuk/Shutterstock)

Other herbs, such as basil, sage, rosemary, and thyme are also excellent at repelling pests, as well as being delicious in their own right. And of course, no companion garden would be complete without marigolds, with their pungent aroma and bright golden hues.

On the other hand, remember that some plants, in addition to deterring or confusing insect pests, also attract beneficial insects. The highly versatile and beautifully scented lavender is a favorite of bees, butterflies, and hoverflies, which will pollinate your veggies. Hoverflies also have larvae that devour aphids at an astonishing rate.

So before planting, consider who would make good neighbors. Who will ward off foes? Who will attract friends that everyone in the garden can benefit from? Make your garden a neighborhood that Mr. Rogers would have liked to live in, where everyone helps out in one way or another—a garden full of companions, all working as a team. We could learn a lot from plants.

EJ Taylor is a UK-based environmental biologist, entomologist, and teacher with over 20 years of experience in working internationally. Ms. Taylor holds a fascination for the natural world and the relationships between species. Of particular interest are the effects of the natural environment on human well-being, mental health, and cognition. When not surrounded by nature, Ms. Taylor can be found creating artwork, cooking, pottering in the vegetable garden, or traveling (sometimes on a classic British motorcycle).
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