A dethatcher or lawn scarifier is a device that removes

thatch Thatching is the craft of building a roof with dry vegetation such as straw, water reed, sedge (''Cladium mariscus''), rushes, heather, or palm branches, layering the vegetation so as to shed water away from the inner roof. Since the bulk of ...

from

lawn A lawn is an area of soil-covered land planted with grasses and other durable plants such as clover which are maintained at a short height with a lawnmower (or sometimes grazing animals) and used for aesthetic and recreational purposes. ...

s. Types of dethatchers include motorized dethatchers or those that can be pulled behind a garden tractor.

Thatch removal (dethatching)

Scarification or de-thatching of lawns or turf is a mechanical process whereby the surface and subsurface of the lawn, green or sports pitch is rigorously abraded by penetrating metal blades, tines or prongs. The process is usually carried out by machines of a professional standard which are normally powered by gasoline engines. Smaller, less rigorous electric machines are also available for the domestic market. The process of scarifying is designed to remove thatch from lawns. Thatch is a build-up of organic matter which can include dead grass, leaves, stems, stolons, rhizomes and overcrowded grass roots and lateral weed growth. Thatch can stifle the growth and health of grass or

turf Sod, also known as turf, is the upper layer of soil with the grass growing on it that is often harvested into rolls. In Australian and British English, sod is more commonly known as ''turf'', and the word "sod" is limited mainly to agricult ...

. Removing the thatch helps the grass by encouraging it to thicken up and also makes it stronger and less susceptible to disease. Reducing thatch levels increases the levels of water, air and nutrients that can get through to the root zone of the grass plants. Significant thatch problems in lawns can cause diseases and can encourage moss to grow in the areas where grass has died. A by-product of scarifying or de-thatching is that moss is also removed, and depending on how deep the scarifying blades are set, root cutting can also occur, and this in turn helps grass to thicken up over time. Scarifying is normally carried out in autumn or spring. When scarifying or de-thatching, not all thatch should be removed as a small amount of thatch is beneficial to the lawn. A lawn that has excessive thatch may feel spongy when trodden upon. After removing thatch, it can be swept or raked up using a lawn sweeper.

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{{Garden tools Gardening tools Horticultural techniques Lawn care