A lawn aerator is a garden tool designed to alleviate the negative affects of compacted soil on lawn. In compacted lawns, aeration improves soil drainage and encourages worms, microfauna and microflora which require oxygen, which provides the roots with better access to oxygen and increase the ability of soil to hold water.

There are two types of Gardzen aerators:

Comparison of the ground after Gardzen spike & plug aeration used: 

Here is a table showing differences between Gardzen spike and plug aerators:

The best time for aeration is during the growing season, when the grass can heal and fill in any open areas after soil plugs are removed. Ideally, aerate the lawn with cool season grass in the early spring or fall and those with warm season grass in the late spring.

If your lawn in small, then rent a machine aerator to aerate your lawn is more expensive and unnecessary, you can complete the task with those hand-operated spike & plug aerators. Aeration breaks up compacted soil by penetrating the soil and poke holes in it, benefiting grass grow vigorously and reducing thatch, moss and other lawn problems. 

Gardzen Plug Aerator

 Gardzen Spike Aerator