Crosschecking was a way of planting corn so that there was an equal distance (38 inches) between the north and south rows and the east and west rows. A wire was threaded through a device in the planter and stretched across the length of the field. Each time a knot in the wire passed through the device, it triggered the planter to drop three kernels into a hill. In a field of crosschecked corn, a farmer could cultivate north and south to cut weeds and later take a swipe at them driving east and west. Later when chemicals became popular for controlling weeds, a field didn’t need as much cultivation, and farmers started planting 30-inch rows in one direction.