FIRST OF ALL: WHAT IS SCALPING A LAWN MEAN
Lawn scalping refers to cutting your lawn grass quite low, so low that you expose the stems of your grass blades. Typically, scalping is done intentionally by setting the mower to its lowest height, but you can also accidentally scalp areas of the lawn. This accidental scalping happens when your lawn is uneven or bumpy and the mower hits a low spot. Grass that becomes so long that it bends over and creates thatch can also cause you to scalp your lawn as the mower cuts near the base of the blade rather than the tips.
Problems with Scalping
Many extension services advise against scalping your lawn due to its damaging effects on the health of your lawn. One problem is that grass blades photosynthesize to provide food to the roots. By chopping off the majority of this blade, you reduce the amount of energy the roots receive, and this makes for a weak lawn that is more susceptible to stress, insects and disease. Another problem with scalping is it encourages weed growth. Without the dense grass blades to block light, weed seeds are allowed to germinate and grow. In a scalped lawn, weeds can quickly dominate. Also, although not a problem in mild areas, the exposed stems of scalped lawns can be damaged by a sudden spring frost.
Benefits of Scalping
Although generally not recommended, scalping is advised by a few extension services, such as Mississippi State University Extension Service. Scalping helps clear away any winter debris from your lawn and exposes the soil to more sunlight. This extra sunlight helps warm the soil. Scalping is also beneficial if you have an uneven lawn, since the short turf makes it easier to see and fill in the problem areas of your lawn. If you do intend to scalp your lawn, do it soon after the grass wakens from winter dormancy. This gives the grass the rest of spring to recover.
Best Mowing Practices
Because scalping your lawn can cause more harm than good, it's better to stick to good mowing habits. Mow your lawn at least once a week. During the spring, when grass is actively growing, you may need to mow every three to four days. Your first spring mowing can be slightly lower than normal, but to avoid scalping only set your mower one setting lower than normal. After this initial mowing, set your mower so you remove only one-third of the blade height and aim to keep the blades at the height recommended for your grass species.