A lawn mower dethatcher cuts through the dense layer of organic material containing dead grass roots, living grass roots and other decayed material with a series of sharp cutting knives. Dethatching a lawn allows oxygen, nutrients and water to reach deep into the roots of living grass. Another benefit of dethatching a lawn is that it promotes new grass growth in mature lawns, increasing lawn density. All dethatchers work on the same principle but vary in the method in which they move across a lawn. Push-style dethatchers rely on an operator to move them across a lawn, and dragging dethatchers connect to an attachment point on a lawn tractor.
Push-style dethatchers are either self-propelled or rely solely on an operator to push them forward and typically resemble a large push mower. Both styles are effective at lifting thatch away from grass, roots but self-propelled models are easier to move across lawns with small inclines. Maintenance on a push-style dethatcher includes checking for bent blades, blade sharpening and regular oil changes. Keeping a lawn mower dethatcher in good working order will alleviate problems while dethatching a lawn. Dethatching large lawns or lawns that have steeper inclines requires a lawn mower dethatcher with more power than a push-style version.
Dragging dethatchers attach directly to a lawn or garden tractor. The blades of this style of dethatchers use the forward motion of the tractor to turn the dethatching blades or have a dedicated motor mounted above the dethatching blades. Both styles will dethatch a lawn, but a dethatcher with a dedicated motor is more effective at lifting the thatch above grass roots. Like push-style dethatchers, dragging-style dethatchers require regular blade maintenance and oil changes on motorized models to ensure they work properly.
Other factors have a role in how effective a lawn mower dethatcher works on removing thatch from a lawn. The moisture content of the ground below the lawn plays an important role in the ability of a lawn mower dethatcher to lift thatch. Hard, dry soil does not allow the blades of a dethatcher to penetrate deep in the ground and can cause damage to the ends of the dethatching blades. Two types of blades are common on all styles of lawn mower dethatchers: stiff-cutting blades cut deep in the ground to lift thatch, and spring-style blades put less stress on a lawn but are less effective for removing thatch.