It’s pretty simple:  Green means GO, and red means STOP!  If the chart says green, the plants work well together.  If the chart says red, the plants don’t work well together.  

http://onecreativemommy.com/planning-the-garden-companion-planting-free-printable-helpful-insects/

Graciela Iturbide

Microbial Connections Between Animals

http://www.nature.com/articles/sdata201549