The study of plant microbiomes has skyrocketed in the last fifteen years and from this it is clear that microbiomes play crucial roles in many biogeochemical processes from immune function to development, but they are also sensitive to environmental change. While there has been a plethora of studies on plant microbiomes, they remain limited by a short list of plant host species and geographic area. Here I will present on what plant groups and habitats have been studied and what areas are still in need of more research. I propose the need for a repository of information to tackle patterns and changes in plant microbiomes on a global scale. Such a repository will engender further microbiome studies, and help to address the urgent need for setting a baseline across plant hosts and ecosystems. My assessment of the studies conducted thus far will lead to a discussion on designing future plant microbiome studies that capture the necessary metadata to make sense of these patterns on a global scale.