Core aeration removes small plugs of soil so air and water can move more readily into compacted turf. Consider a strip of lawn between a parking lot and a front door. If people take that shortcut every day, the soil beneath can become dense even while the rest of the lawn grows well.
Look for a pattern of wear
Start with the turf that receives the most traffic. Compare it with an undisturbed area nearby. Does water sit on the worn strip after rain? Does a probe enter the soil less readily there when the two sites have similar moisture?
Those observations can point toward compaction, but they do not explain every thin patch. A downspout, deep shade or a grading problem can also leave turf struggling. Mark those conditions separately so the treatment matches the cause.
Know what the machine leaves behind
A core aerator has hollow tines that remove soil and deposit plugs on the surface. That differs from a solid spike that simply presses into the ground. The plugs can look messy for a while, then gradually crumble back into the lawn.
Late summer and early fall often suit Minnesota cool-season grass because the lawn can recover during active growth. Soil should support the equipment and allow the tines to penetrate. Muddy ground and extremely dry ground can both complicate the work.
Mark the things a crew cannot see
Flag irrigation heads, shallow lines and invisible fence locations before the visit. Point out narrow gates and slopes. If you plan to overseed, tell the crew about recent herbicide use and ask how the two jobs fit together.
Review the University of Minnesota’s lawn care calendar. For aeration in the Mankato area, describe the worn areas and what happens after rain. That helps us determine whether core aeration fits the site.