Funny story (not so at the time). I was new to my PG magnum, applied high iron fert to a 3 acre lawn at a 3 million dollar house, going back-and-forth pattern. Neighbors started commenting on the 'huge mower' that must have left those 20' wide 'stripes' in the lawn. haha. I now use the 'Nascar' method, roundy round to the left, and have no more striping problems.