Using variable temperature scanning tunneling microscopy vicinal surfaces of Ge(100) have been studied in a temperature range between 80 and 300 K (room temperature). Annealing the sample gives rise to a nonuniform terrace and step distribution. Terraces with dimer rows perpendicular to the step edges cover approximately 3/4 of the entire surface. At room temperature about, of the surface is covered by buckled dimers. Dimers of straight SA steps are always pinned, i.e., they appear in their buckled form. On top of terraces buckling is also found, associated either with kinks in the step edges or in the formation of a single antisite dimer. At 80 K all dimers appear asymmetric in c(2x4) or p(2x2) geometry. A transition between both structures may occur due to sample-tip interaction which indicates that the energies of both reconstructions are rather similar.