Unlike regular aeration, where solid tines simply punch holes in the ground, core aeration removes a plug of soil from your lawn at the same time. Plug or core aerators do this by using hollow tines that puncture the surface and then pull the plugs from the ground on their way back out.
Core aeration can be done with manual hand tools but is much easier to undertake with a specialised coring machine. The primary reason we need to undertake aeration, core aeration in particular, is to alleviate issues related to compaction. Compaction is a common problem for homeowners and can be caused by many factors including; regular foot traffic, driving on your lawn, sport activities and general use of your lawn. What compaction does is prevent oxygen, nutrient and water from being able to penetrate properly to the roots of your lawn, which in turn leads to poor lawn health. Core aeration is a great way to alleviate these compaction issues.
After core aeration, you will be left with lots of holes through the lawn where the plugs were removed, and the cores will be left behind on the surface of your lawn. These cores will breakdown over a couple of weeks and can be helped along with irrigation. If you don’t like the appearance and you want to break them down quicker, you can rake across them with the back of the rake, breaking them apart and allowing the dirt to fall back into the holes. Mowing over the plugs will also help break them apart and spread the dirt back into the profile. You can remove the plugs completely from your lawn if you prefer, but you will only be removing nutrient that would be much more beneficial put back in your soil profile.
Make sure you only core aerate when your grass is actively growing during the warmer months, so it can recover quickly. The best time to use a core aerator is when the soil is hydrated but not overly saturated with water. When the soil is dry it will crumble inside the tines, preventing proper removal of the cores from the ground. On the flip side, if the soil is too wet it will lodge itself inside the tines.
After coring your lawn is a great time to top dress with washed river sand. The sand will fill the holes and enable air and water to penetrate due to its free draining, open structure.