Core Aeration Best Practices: Depth, Hole Density, and Pattern for Healthy Lawns

Q: I got this from my lawn company when I asked about aeration:

We provide core aeration but not the Criss-cross method. It causes too many divots from tires (repeated 180° turns). We prefer the circular method—few divots, equally good results. Also, if the lawn is sufficiently moist, secondary passes mash previous holes closed. Most companies don't use criss-cross. If you insist, rent aerators for ~$60/day.

For lawn aeration, I recommend:

Penetration depth depends on soil type, moisture, tine diameter, and aerifier weight/power. Leave soil cores on lawn to break down via rainfall and traffic. If appearance bothers you, rake them in. Go over the lawn twice: once in one direction, then perpendicular for best results.

From Aerating Lawns:

Remove cores ½-⅝ inch diameter, 3 inches long. Aerate when soil is moist. Avoid dry or excessively wet soil. Properly aerated lawns should have 20-40 holes per square foot. Most machines need several passes. After aeration, drag lawn to break up cores.

Personally, I think 10-12 holes per square foot suffices for adequate aeration.