Aerating your lawn helps improve drainage and gives the roots room to spread out to ensure a healthier, fuller appearance. Some lawns need aerating every year, although most can go two to three years before needing aerating -- which is good, if you don't like the look of brown plugs on your lawn. You don't have to rake the plugs left by aerating, but doing so gets nutrients back into the soil faster. And, it might give your kids something to do.
A lawn plug aerator pulls narrow, cylindrical clumps of dirt out of your lawn, usually 2 to 3 inches long. Proper aerating makes two passes over your lawn, pulling plugs 2 to 3 inches apart with each pass -- that leads to a bunch of ugly, brown plugs sitting on top of the grass. The holes left in the ground reduce compaction in soil, which keeps water and nutrients from getting to grass roots and allows the roots to spread freely. Aerating also helps breaks up the thatch layer. Always use a plug aerator, because those with solid spikes don't aerate the soil correctly.
Don't panic when you first see you newly aerated lawn. It might look like it just rained giant dirt plugs. These plugs are full of nutrients, and leaving them on the grass allows them to break down naturally to return nutrients to the soil below. Watering your grass helps the plugs break down without raking, although it can take a week or two for the plugs to disappear completely.
Breaking Up Plugs
If you can't stand the sight of those plugs on the lawn, it's fine to use a rake to break them up. You don't need to rake them off your grass completely. This removes nutrients that could help your grass grow. Running the back of a fan-style leaf rake over the clumps or beating them gently with the back of a steel garden rake breaks the plugs up, allowing the dirt to fall in between the blades of grass. Flip the rake over and run the tines over the top of the grass to help push the dirt down, but don't pull so hard you start gathering the plugs together. Mowing over the plugs also helps break them up and distribute the dirt.
Raking up the plugs and removing them from your lawn improves the appearance immediately, but it takes vital nutrients away from your grass. When you want to rake the plugs, such as when you want to add the plugs to your compost pile, replace the nutrients by spreading compost over the aerated lawn and water it in thoroughly. The compost falls into the holes left by aeration to replenish nutrients and feed your grass.