Companion planting is the practice of growing two plants side by side, in a way that benefits each of them. Often, we think of it as a natural means of pest control, with one plant guarding the other from bugs.
But according to Gardener Scott companion planting pest control is one of the biggest gardening myths.
In a live stream Q&A on YouTube, he says that there isn’t much evidence that companion planting really works as a way to keep pests away from plants.
Answering questions from fans, he explains that if you’re paying attention to your garden, then chances are your plants will grow healthily. ‘A good garden grows where a good gardener goes,’ he says.
‘Many people think of companion planting as pest control, and that is seen as the exclusive reason to companion plant,’ Gardener Scott says. ‘You grow one plant because it deters a pest from another plant, or you’re growing a plant because it is a magnet plant; it attracts pests away from another plant.
‘There are fewer benefits than you might think,’ he says. He goes on to explain that much of the evidence out there is that companion planting is not that effective as a form of pest control. ‘There isn’t a lot of research on it,’ he adds.
He takes the example of marigolds, whose aroma is commonly believed to deter aphids. Gardener Scott says that this simply doesn’t play out in laboratory studies.
Of course, there’s nothing wrong with growing marigolds in your garden, and they may attract wildlife to your garden. They just might not be effective in deterring aphids. But as long as your plants are getting enough sunlight, nutrition and water, you can grow your plants together without problems.
Another thing to note is that a lot of the evidence around companion planting is anecdotal – for example, the idea that growing basil near tomatoes will infuse tomatoes with basil’s scent.
We’ll be relaxing our approach to companion planting and if there’s space on our wigwam where we’re growing peas, we’ll add something else without worrying we’re doing it wrong.