I also enlarge my garden about 2'/year. Hubby calls it "garden creep". He loves his lawn... I love my garden... so our irreconcileable difference results in garden creep. Kind of like evening up the borders on the brownies in reverse. Gotta keep those borders even... so if things get a bit crooked, the answer is to enlarge the edges to square things up again! This year's garden creep occurred in the form of a hay bale border.