Low temperature hydrothermal methods allow for growth of nanowires on novel substrates. We examine the impact of variations in chemical concentration, time, temperature, and seed layer on nanowire (NW) growth and crystallite formation. The majority of growth (NWs and crystallites) was found to occur within the first two hours. Lower Zn(NO3)2 concentrations produced a reduction in the undesired large crystallites, whereas hexamethylene tetramine (HMT) concentration did not largely impact crystallite density or nanowire morphology. Growth temperature appeared to impact NW diameter variation. Nanowires grow only on the ZnO seed layer and crystallites seem to attach preferentially to the bare Kevlar surface.