3 Common Companion Planting Myths, and What Actually Works in a Real Backyard Garden

Have you heard the gossip? Rumor has it that tomatoes LIKE basil.

Well, not really. But a quick internet search for "companion planting" unearths an endless list of articles that portray different combinations of plants as either best friends or the biggest foes. We may have taken the "companion" in companion planting a little too far. This is an unfortunate misrepresentation, as some combinations of plants really are effective.

"While online rumors abound, there are many well-established (both through scientific research and through trial and error of generations of gardeners!) companion plants that can be beneficial in the garden", says Dr. Flora Krivak-Tetley, the Research Director at Cedar Circle Farm & Education Center in East Thetford, Vermont.

Let's dig into companion planting a little more and separate the myths from solid research.

1. Companion Plants Can Increase Crop Yields

This is the most common companion planting myth: Growing flowers next to vegetables will give you a larger veggie harvest.

The Reality

Flowers don't spontaneously create heads of broccoli but they can help lure beneficial insects into the garden. And those beneficial bugs can in turn, support healthy crops. Krivak-Tetley recommends adding plants that attract predatory insects. Nectar-rich sweet alyssum, for example, attracts hoverflies and parasitic wasps, which also consume nuisance aphids. Fewer aphids can mean larger garden yields.

Colorful, nectar- and pollen-rich ornamental flowers can also help attract beneficial bees, butterflies and other pollinators to the garden. While some plants are self-pollinating, others require a little assistance in transferring pollen between plants. Cucumbers, melons, pumpkins and berries, for example, rely on wind, rain, and pollinating wildlife to move pollen from flower to flower. And pollinated flowers are a prerequisite for fruits.

So, while flowers don't necessarily "make" your summer squash plant produce more squash, luring pollinators into the garden can increase the odds that your squash plant will receive a visit from a passing bee. Borage, calendula, cosmos and nasturtium are among some of my personal favorites and are attractive to both people and pollinators.

2. Plants Can Impact the Flavor of Other Plants

The most common example of this myth is the belief that planting basil next to tomatoes will make them taste sweeter.

The Reality

Plant flavor is shaped by a combination of genetics and environmental factors, including weather conditions, soil type and pressure from garden pests. Flavor results from different biochemical compounds that a plant naturally makes: it's what makes a tomato taste so different from a blueberry.

While the environmental conditions won't change the genetics of a plant, it does have an impact on how the plant grows and releases those biochemical compounds. Extreme heat, for example, can make plants like lettuce, cilantro and chervil suddenly flower (bolt), rendering them bitter. A stressed, unhappy plant will produce poor quality fruit, fewer fruit or no fruit at all.

So what about that basil? "There has been some (limited) research into the tomato-basil pairing and it has confirmed that tomato plants respond to basil neighbors with more vigorous growth and the development of stronger root systems," says Krivak-Tetley. "A recent study explored mechanisms and found that basil volatiles (those chemicals that smell really good!) change the way tomato plants respond to wounds and pest damage, priming the plants to be better defended throughout the season-and thus healthier and more robust."

3. Fragrant Herbs Deter Insect Pests

Example: The strong scent of marigolds repels garden pests.

REALITY

Uber-fragrant marigolds are extolled as the ultimate champions of garden pest prevention. This is partially true, but also somewhat exaggerated. There is, in fact, heaps of research indicating that marigolds are specifically effective at controlling soil-borne nematodes, microscopic pests that infect the roots of tomatoes, peppers and numerous other crops.

However, marigolds repel nematodes by releasing a toxic compound (alpha-terthienyl) from their roots. The scent of marigold alone isn't enough to deter nematodes; marigolds have to be planted and left in the soil for entire seasons in order to be effective.

Nevertheless, marigolds are darling additions to the garden. Personally, I tuck a few in along the edge of my veggie beds every year, purely because they add color to a bed full of green and brown, and I love their nostalgic fragrance. I have no idea if they are actually keeping nematodes out of my tomatoes, but that's fine with me. Plant them if you love them.

What Actually Works

All of this is not to say that companion planting is useless, or that plants don't affect each other in your garden. Some companion planting techniques do make a difference to the health and appearance of your garden.

Intercropping

Instead of traditional single-crop rows, planting a layered, diverse assemblage of crops can make for a garden that is more productive. Referred to as "interplanting" or "intercropping", this practice pairs plants with different environmental needs together in the same space.

"Compatible plants will often have different rooting depths, different nutrient or light needs, and/or different heights so they can be planted close together", says Krivak-Tetley. Shade-loving lettuce can be tucked underneath tall, leafy corn. Shallow-rooted radishes can be planted in between deep-rooted tomatoes. Plants with different growth habits can occupy the same garden bed without competing over resources.

Sometimes plants aren't good companions, but simply, good neighbors.

Planting With Soil in Mind

Plant a rotating cast of heavy feeders (tomatoes and corn), and soil-aerating root crops (carrots). This ensures the garden bed remains fertile. Include nitrogen-fixing legumes, like beans and peas, which actually help nourish soils by converting atmospheric nitrogen into a form more usable by plants. As always, don't forget to add compost!

Planting a strategic combination of cool- and warm-season crops that mature at different times means the garden bed will always have something in it. No gaps means that there won't be any exposed topsoil left to get compacted by wind and rain, and weeds won't have an opportunity to take over the bed.

Prioritizing soil health helps ensure a resilient, thriving garden for many years to come; feed the soil, and the soil will feed you.

Final Thoughts

Like everything in gardening, sometimes you just need to plant it and find out for yourself. "My main piece of advice is to start simple! Companion planting doesn't need to be complicated and a few small additions to your garden can help", advises Krivak-Tetley. "Try adding a couple companions this season and see if they work for you."

Related: Best Companion Plants for Cucumbers

Copyright 2026 The Arena Group, Inc. All Rights Reserved

This story was originally published April 21, 2026 at 8:15 AM.