Earthworms are generally considered to be beneficial, so trying to control them is unusual. Even more unusual is finding information about “control” methods. However, after some searching, the following ideas may help you discourage earthworm activity. Earthworms usually come to the surface after a rain or after the soil has been made excessively wet. Therefore, keep the area as dry as possible. Divert rain water (down spouts) away from the area, if possible.