Does the old concept of companion planting have any science behind it?

As an obsessive plant collector with little impulse control, I will take any excuse to cram a few more species into my tiny plot. So the concept of companion planting, an old belief that adding certain plants around existing crops can boost pest resistance, yields and even flavour, is one that has always appealed to me. But as a sceptical scientist, I’m curious about how well these claims actually stack up. Let’s dive in.

The tricky thing with examining the science around companion planting is quite how…