What is the difference between a dethatcher and a scarifier?

Scarifiers and dethatchers are both tools used to remove thatch from lawns. The main difference is that dethatchers are less intense, for addressing light to moderate thatch levels with metal tines, while scarifiers are more disruptive to your lawn, using metal blades to cut more deeply into the soil. Otherwise, the actual equipment might be identical. A scarifier/dethatcher can do either job by simply changing out an attatchment.

Scarifiers and dethatchers come in many forms, from manual models to tow-line scarifiers that can be pulled behind a tractor. A tow-behind dethatcher is a simple wheeled device with multiple prongs extending from it that can be towed behind a tractor or riding lawn mower. The prongs drag along the ground to loosen built-up thatch and make a lawn healthier.

Proper timing is crucial, or dethatching and scarifying can harm your lawn instead of help. Read this article for advice on whether the thatch in your lawn needs attention, and if so how much and how often.