The best time to aerate is in the spring once the grass starts to green up a bit or in the early fall before the grass goes dormant.

Unlike power raking aeration can be performed when the grass is wet or it is raining a bit. A moderate amount of wetness is ideal as it allows the tines of the aerator to get deeper into the ground. Too much wetness makes the process too messy. The day after a rain storm is often the best time to aerate.

For lawns with compacted soil or high traffic it is recommended to aerate once a year either in the spring or fall. For healthy lawns once every other year is often sufficient.

For lawns with thick thatch buildup which is common in healthy lawns power raking is more beneficial as it breaks up the thatch layer more than aeration. For a lawn with more compaction issues aeration is more beneficial for reducing compaction.

Some people like to remove the cores for aesthetic purposes, however the cores sitting on top of the lawn act as a top dressing and will break down from the micro-organisms in the lawn returning the nutrients to the lawn. It takes about two – three weeks for the cores to break down.