Scalping refers to intentionally cutting grass at an extremely low height, removing most leaf tissue and exposing the underlying runners and soil. While this aggressive spring cleanup is recommended for some turf types to remove dead winter foliage and promote faster green-up, it is detrimental to St. Augustine grass. Cutting this warm-season grass down to the soil line or its lowest mower setting causes significant stress and harms the lawn’s long-term density.
Understanding St. Augustine Growth Habits
St. Augustine grass has a unique growth structure that makes it highly susceptible to damage from low mowing. Unlike turf varieties such as Bermuda grass, which spreads using both above-ground stolons and underground rhizomes, St. Augustine only uses above-ground stolons. These stolons are thick stems that creep horizontally along the soil surface, rooting at nodes to produce new vertical grass blades.
The actively growing point, or crown, of the St. Augustine plant is situated relatively high up on these stolons, just above the soil line. Since the entire growth mechanism sits exposed on the surface, cutting the lawn too short removes these crowns completely. This structural difference means the plant cannot rely on robust underground rhizomes to store energy or initiate new growth after a severe cut.
Consequences of Scalping Damage
The most immediate consequence of scalping is physical shock and sun scald. Removing the thick canopy exposes the tender stolons and bare soil to direct, intense sunlight. This sudden lack of protection causes the exposed plant tissue to dry out and turn brown, significantly delaying the spring green-up homeowners seek.
Exposing the soil also creates an ideal environment for weed proliferation. Dense turf naturally suppresses weed seed germination by blocking sunlight, but scalping removes this protective layer. Weed seeds receive the light and warmth necessary to germinate before the highly stressed St. Augustine can recover and rebuild its canopy.
The recovery process for St. Augustine is significantly slower compared to rhizomatous grasses. Since the growing crowns are severed during scalping, the plant must expend limited energy reserves to initiate growth from the remaining stressed stolons. This prolonged vulnerability results in a patchy, thin lawn and makes the turf more susceptible to common warm-season pests and diseases during recovery.
The Recommended Spring Cleanup Technique
Instead of a single, drastic scalping cut, the correct spring cleanup involves a gradual reduction in height to remove accumulated dead leaf material, or thatch. Begin a routine mowing program as soon as the grass shows signs of active growth, typically when soil temperatures reach 65 degrees Fahrenheit. Set the mower blade slightly lower than your regular summer cutting height, usually between 2.5 and 4 inches for this species.
The goal is to remove the dead, brown material without damaging the green stolons or the growing crowns. Never drop the mower to its lowest setting, which can cut the stolons and cause damage below the recommended minimum height of 2 inches. If a large amount of thatch built up over winter, gradually lower the deck height over two to three successive mows. Remove no more than one-third of the leaf blade in any single cutting event.
It is beneficial to use a bagger attachment or thoroughly rake up the clippings and debris during this initial cleanup. Removing this dead material prevents it from smothering new growth emerging from the stolons and allows sunlight to penetrate the soil surface. This careful, gradual method effectively handles winter debris while preserving the plant’s growth structures, leading to a healthier, more robust lawn.