[dropcap]T[/dropcap]he idea of having two or more plants growing next to each other to the mutual benefit of each has been around for thousands of years. Beyond this basic concept, it is actually more controversial than one might anticipate. (But then isn’t everything these days!) 

Research shows that certain plants emit compounds and chemicals that create positive and negative growing environments for their surrounding neighbors.

Many assumptions are also derived from years of pass-along ...