
Lawns or areas of lawns become scalped when either high points are severed off when mowing an uneven lawn, or when too much leaf material has been removed in a single service.
Uneven lawns can often occur with newly laid roll on lawns where the lawn rolls are never the same thickness. In many cases the problem can self-rectify with a regular lawn mowing regime matched to the lawn variety. This allows the soft soil and new turf to settle and even out. The high points will continue to be cut back until the correct height is achieved and the area is repaired. Any sunken points should thicken up its thatch layer to become even, If this doesn’t happen, light top dressing should be considered to repair the problem.
When too much leaf material has been removed in a single lawn mowing, it leaves the brown thatch layer exposed, which quickly dries and leaves an unsightly appearance. If cut too short in relation to the original length of the grass, the crowns of the lawn may also be damaged, killing the affected lawn area completely. This is because whenever lawn grows, not only does the green leaf grow taller, but the crowns and thatch layer underneath also raise higher.
The problem is entirely due to the lawn being mowed too infrequently for its growth rate, leaving the lawn in a continuously damaged state with an ugly appearance and at risk of being killed from the lawn mowing. Raising the height of mowing may seem to alleviate the problem, but what is actually happening is the thatch layer and crowns are being raised to a higher height at an even faster rate due to the longer leaf being left on the lawn, increasing photosynthesis and the food supply. Eventually the increased thatch layer will catch up to the mowing height and the problem will become much worse. The inclination to cut back the thatch when mowing may easily kill the lawn altogether.
Severely thatched up lawns will continue to be scalped until vertimowing is undertaken to repair the lawn.
The only solution to maintain a proper lawn care regime and to mow at the correct height and at the correct frequency, which is matched to how fast a lawn is growing at any given time of the year.
Def: crown (in lawns): the main growing apparatus of the turf plant, which sends out leaves, shoots runners and roots. If damaged, the crown cannot repair and will kill the rest of the lawn plant it supports.
Highly respected Australian turf and plant breeder Todd Layt shares expert lawn care advice with homeowners on The Lawn Guide.