In this Reply, we provide a detailed analysis of experimental data for the nucleation of metal rows or islands during deposition of Ga on Si(100) quantifying the influence of defects. Contrasting the proposal of Kocán et al. [Phys. Rev. B 74, 037401 (2006)], we find that this process is not dominated by heterogeneous nucleation at C defects. We also argue that such heterogeneous nucleation could not in itself be responsible for the unusual monotonically decreasing island size distributions observed in this system. In addition, we offer possible explanations for why behavior observed by Kocán et al. for In deposition on Si(100) appears to differ from that for Ga deposition.