Of all the things you can do to help your lawn, PUNCHING IT OUT is probably the best. By that I mean punching holes in it with an aerator, not your fist.
Lawns in southern Canada and the northern United States benefit from one or two core aerations per year -- Spring & Fall -- with Fall being the preferred time of year if it is only being done once.
What is lawn aeration?
Using a machine to remove soil cores from a lawn and leaving them on the lawn's surface to breakdown reduces compaction, improves grass rooting and helps control thatch build-up. Core aeration also speeds applications of lime and fertilizer down into the root zone.
It’s important that the soil is moist enough when aerating, since it will aid in the removal of longer and deeper soil cores. On the other hand, soil conditions should not be muddy. Going over the lawn multiple times will add to the benefits of core aeration, and that is especially recommended if you are overseeding the lawn afterwards.
Most equipment rental yards have core aeration machines, and neighbors can go together on the rental cost to share the machine and save money.
Benefits of lawn aeration
> Reduces soil compaction
> Improves grass rooting
> Prevents thatch build-up
> Promotes thatch breakdown
> Improves drought tolerance
> Enhanced fertilizer uptake
This job can be like a work-out at the gym, depending on how large and steep your lawn is, but it is well worth the effort to help keep your lawn healthy. Once a year is good, twice a year (fall and spring) is even better!
Be sure to mark and avoid anything with 6-inches of the lawn surface that could be damaged by the steel tines on the aerator. This would include electric dog fences, utility access caps, shallow cable lines, sprinkler heads, etc.