If you have a lawn, sooner or later there will come a time when you need to dethatch and or aerate it.
What is Thatch?
Over time, little bits and pieces of grass die and gather to form a barrier just above the soil. This is called thatch. A little bit of thatch can be beneficial. It's organic material that is broken down by microbes in the soil. But sometimes, thatch builds up too fast for natural processes to break it down. It forms a barrier, keeping moisture and air from going where your grass needs it. One-half an inch or more of thatch can weaken your lawn.
You have 2 ways to remove thatch: dethatching and aerating...aerating being the easiest and perhaps most effective way to go.
How to Dethatch
If you have a small patch of lawn and don't mind a little exercise, you can use a covex rake to detach the lawn. As you pull it through the grass, it lifts up and moves the thatch. Chances are, you'd prefer a power rake or dethatcher, which can be rented at your local tool rental store. This machine combs your grass and kicks out a large amount of debris, which you'll have to rake off afterwards. If you live in a warm climate, be sure to ask if the machine you're renting is suitable for your type of grass.
When to Dethatch
For cool-season grasses, the best time to dethatch is late summer or early fall. That's when your grass is growing most vigorously. For warm-season grasses, dethatch in late spring or after the second mowing.
Before dethatching, mow the lawn grass a little shorter than you normally do. Also, you'll achieve better results if you do it after a light rain or watering, when the soil is damp.
Aerating vs Dethatching
Aerating, coring, and aerifying are different terms you might hear for the same procedure. A core aerator you rent for your local tool rental store pulls plugs out of your soil that you leave on top of the ground. This loosens compacted soil and allows air, water and fertilizers applied to reach the roots.
Aerating is considered a better way to dethatch your lawn since it puts less stress on it. Personally, I always opt for aerating. It's a simpler task to perform and there's no need for raking up the debris after the process.
When to Aerate
As with dethatching, you want to aerate when your grass is at its peak growing season - late summer or early fall for cool-season grasses, or late spring for warm-season grasses.
How Often Should You Aerate?
If you have high-traffic areas and heavy thatch, you might want to aerate every year or 2. If your lawn looks great, you can cut back to every 3-5 years.