Scarifying means to remove “thatch” which is the accumulation of dead and decaying organic matter at the base of the living roots and leaves.

Factors that increase or encourage thatch are:  letting the grass clippings fly and not “boxing off”; poor aeration leading to compaction; poor surface drainage; excessive application of Nitrogenous fertiliser; or acidic soil.  Scarify in the early Autumn.  If a lawn has not been scarified for a long time then the amount of dead and decaying matter that will be removed will be enormous.  But do not be concerned, this operation will only do the lawn good.

Scarification is best done in two or three “passes” in different directions, corner to corner and lengthways.  For the first pass do not set the tines or blades too deep; approx 5mm is ideal.  On the second pass the depth can be set at no more than 10mm and the final pass can be set deeper but not penetrating the soil.  Do not put the “thatch” that is removed on the compost heap because may contain fungal spores.