Grids are very complex and volatile infrastructures that exhibit parallel and distributed aspects. To harness its complexity as well as the increasing intricacy of scientific applications, modern software engineering practices are needed. As of today, two major models dominate: software component models that are mainly based on spatial compositions and service oriented models with their associated workflow languages promoting temporal compositions. This paper unifies these two forms of composition into a coherent spatio-temporal software component model while keeping their benefits. To attest the validity of the proposed approach, we describe how the Grid Component model, as defined by the CoreGRID Network of Excellence, and the Askalon-AGWL workflow language have been adapted.