Thatch is a build up of dead organic matter laying on the soil surface. Thatch is a natural occurrence as old grass stems die and are replaced by new ones. Bacteria in the soil digest the thatch breaking it down into nutrients for other plants. In severe cases of heavy thatch the bacteria cannot digest all the organic matter and the thatch builds up and forms a fibrous layer on the soil surface. This layer acts like blotting paper preventing the flow of moisture, oxygen and carbon dioxide to and from the grass roots.
It is vital that thatch is not allowed to build up as it can have a disastrous effect on any lawn weakening the grass, encouraging moss and diseases . Scarifying is the physical process of removing thatch from the soil surface. It used to be carried out by using a wire rake. Devon Lawn Care have powered machines that scarify far better than raking. Several vertical metal blades revolve at high speed around a shaft and dig into the ground as the machine is pushed along the lawn. The blades can be set at various heights from the surface and consequently take out various amounts of thatch etc. As well as removing thatch and dead moss the blades also prune the shoots of the grass plant encouraging stronger growth.
Scarifying is more vigorous and effective than raking or using an electric lawn rake which tend to just take our some of the thatch. Scarifying pulls the dead moss and thatch out of the lawn and in the short term makes the lawn look far worse before it recovers. It is important to schedule scarifying so that it is followed by the appropriate weather conditions that assist the lawn with its recovery. Never scarify without previously applying some moss control 2 to 3 weeks in advance. If you scarify without applying moss control you are spreading moss spores across your lawn. Devon Lawn Care can advise if your lawn requires scarifying but most lawns benefit from scarifying at least every 2 to 3 years depending on soil and weather conditions.