Lawn leveling, often called top dressing, is the process of applying a thin layer of specialized material over the turf to smooth out surface irregularities. This practice addresses dips, bumps, and shallow depressions that develop over time, restoring a uniform appearance. Leveling is particularly important for St. Augustine grass because this variety spreads horizontally through above-ground runners called stolons. As these dense runners layer unevenly, they create a bumpy surface that makes mowing difficult and the lawn uncomfortable to walk on. This guide provides steps to successfully restore a smooth, uniform lawn surface by integrating new material into the existing turf.
Assessing the Lawn and Timing the Leveling
Identifying areas that require leveling can be done through routine maintenance and physical inspection. A common indicator is “scalping,” which happens when the mower blade repeatedly cuts the grass too short in high spots, leaving brown patches. Homeowners can also place a long, straight edge across the turf; gaps beneath the board reveal depressions that need filling. Poor surface drainage, where water pools after irrigation or rain, also points to low spots requiring attention.
The timing of the leveling process depends on the growth cycle of St. Augustine grass, a warm-season variety. Leveling must be performed during the plant’s period of active growth, typically from late spring through early summer when soil temperatures are consistently warm. Applying top dressing during dormancy, such as in late fall or winter, prevents the stolons from quickly growing into the new material. Leveling during peak growth ensures rapid recovery and allows the grass to quickly incorporate the new material into its structure.
Selecting the Right Leveling Mix
Choosing the correct material is important for the long-term health and swift recovery of the turf. The ideal leveling mix must balance excellent drainage with sufficient nutrient content to support the spreading stolons. A widely recommended composition is a blend of approximately 70% finely screened sand and 30% organic matter, such as high-quality compost or pulverized topsoil. The sand component provides structural stability and porosity to prevent compaction within the new layer.
Using pure sand alone is discouraged because it lacks nutrients and can dramatically change the soil structure, creating distinct layers that impede water and root movement. The inclusion of organic compost ensures the mix retains moisture and supplies beneficial microbes and slow-release nutrients. This balanced material allows water and air to move freely to the root zone while encouraging St. Augustine runners to root quickly. The material must also be free of large stones or debris to ensure a smooth, uniform application.
Step-by-Step Guide to Applying the Top Dressing
Before applying the leveling mix, the lawn must be prepared to maximize the material’s contact with the soil and stolons. Begin by mowing the St. Augustine grass slightly lower than its usual height, typically removing about one-third of the blade length. After mowing, lightly rake or vertically mow the area to open the turf canopy. Removing excess thatch ensures the material settles around the stolons rather than resting on dead organic matter.
The leveling mix should be distributed evenly across the designated areas in manageable, small piles. This prevents the application of too much material in one spot, which can inadvertently suffocate the grass blades and runners underneath. Distribute the piles roughly six to ten feet apart, providing enough material for a thin, uniform application across the target area.
Once the material is placed, leveling begins by working the mix down into the turf canopy. Utilize a specialized leveling rake, a long-handled push broom, or a drag mat to systematically spread the piles outwards. The objective is to move the material back and forth, forcing it down to the base of the grass blades and into the soil depressions.
It is important not to bury the grass completely, as St. Augustine requires its blades to capture sunlight for photosynthesis. The maximum depth of any single application should not exceed approximately one-half inch (1.25 centimeters) over the majority of the area. The grass blades should still be visibly poking through the top dressing after the material has been spread.
When addressing deeper depressions or significant low spots, the material must be applied gradually over multiple applications. If a depression is deeper than one inch, fill it initially with the maximum half-inch layer and allow the grass to recover fully for several weeks. This staged approach ensures the turf is not smothered and maintains the viability of the underlying stolons.
Follow-Up Care and Maintenance
Immediately following the application, a thorough watering is necessary to settle the material. This initial irrigation firmly seats the new material around the stolons and reduces any heat stress caused by the new layer. The water helps the fine particles of the mix filter deeper into the turf’s base, ensuring good contact with the existing soil structure.
For the next one to two weeks, the watering schedule should be temporarily adjusted to keep the new top dressing consistently moist but not saturated. This increased frequency encourages the St. Augustine stolons to rapidly send new roots into the material, anchoring the turf into the newly leveled surface. Deep, infrequent watering should be avoided during this short establishment period to prevent the thin top layer from drying out.
Normal mowing practices should be suspended until the grass blades have successfully grown through the new layer of top dressing. This recovery period typically takes between seven and fourteen days, depending on warmth and sunlight conditions. Once the grass is visibly growing through the mix, resume mowing at the turf’s regular, higher setting. This allows the grass to rebuild its leaf surface area and fully establish itself in the leveled area.