• Healthy grass is aerated once a year for beneficial fertilizing.Peter Dazeley/Photodisc/Getty Images
  
  The process of aerating your lawn involves making holes in the compacted soil to allow water and oxygen to permeate the soil into the roots of the grass. It is important to aerate at the correct time. The time to aerate the lawn is when the grass is just about to begin rapid growth. The type of aerator you use is just as important, and both the spike and core aerators should be compared to find the right one to fit your lawn's needs.
  
  

Spike Aerator

• A spike aerator drives spikes or holes into the soil beneath the lawn. There are six types of spike aerators you can use to prepare your lawn: spike aerator shoes, hand aerators, tow spike aerators, push aerators, mowing wheel aerators, and drum rolling spiked aerators. Spike aerator shoes are affordable with a cost ranging from $10 to $50 and are easy to use by simply wearing them as you mow the lawn. While hand aerators may be more time consuming, they provide the kind of deep holes you need to properly aerate your lawn. A tow aerator attaches to the back of a tractor or powered mower and can punch holes into a large area. These are on the higher end in price, costing up to about $500, as of 2010. Lightweight push aerators are easy to use, but may not provide deep enough penetration if the soil is hard. Weighing them down a bit with a sandbag can be helpful. The mowing wheel has small spikes that work well on moist soil. A drum-rolling, spiked aerator can be lightweight and needs to be weighted down to provide the kind of deep holes that roots need to be nurtured.
  
  

Core Aerator

• Using its hollow tines or spoons, the core aerator punches holes into the soil mechanically. This type of aerator makes deep holes about 2 inches deep and up to three-quarters of an inch in diameter. The deeper holes allow for better sunlight, oxygen and fertilizer to penetrate the soil and cultivate the roots of the grass. Moist soil is best for maximum penetration into the soil. Core aerators leave soil plugs on the surface of the lawn which you can leave unattended and they will work back into the ground. A core aerator can be rented from your local hardware store or a local landscape company will core aerate for a fee.
  
  

Comparisons

• The UGA Center for Urban Agriculture recommends using a core aerator due to having hollow tines that allow for a 2- to 3-inch deep and half-inch wide hole to be placed in the soil to relieve compaction and allow better access for nutrients and oxygen to the roots of grass. While a core aerator may penetrate the ground better, a spike aerator may be easier to operate and can cost less. The holes made by the spiked aerators tend to be smaller than those the core aerators produce, making it necessary to aerate more frequently.