The reflection of a transient plane wave from a grating of thin conducting cylinders is considered. The inverse Fourier transform of the known steady-state solution is performed both analytically and numerically. Both impulse and step function excitations are treated explicitly. Expressions for the scattered fields are obtained that are useful for either large or small time. It was found that a simple decaying exponential function of time is a fairly good approximation for the waveform of the induced current in the grating.