An analytical expression is derived for the current transient due to the diffusion controlled growth of hemispheres in a square array. At short times the current increases due to the growth of individual deposits, while at long times the current drops under the control of linear diffusion towards the surface. It is shown that the arrangement of hemispheres on the plane has a clear influence on the current to the ensemble. The current maximum corresponding to an ordered array is significantly greater, and occurs at a shorter time, than that of an ensemble of randomly distributed hemispheres with the same number density of growth sites.